U.S. patent application number 12/168042 was filed with the patent office on 2009-01-08 for method and apparatus for ablation of benign, pre-cancerous and early cancerous lesions that originate within the epithelium and are limited to the mucosal layer of the gastrointestinal tract.
Invention is credited to David S. Utley, Michael P. Wallace.
Application Number | 20090012518 12/168042 |
Document ID | / |
Family ID | 40222051 |
Filed Date | 2009-01-08 |
United States Patent
Application |
20090012518 |
Kind Code |
A1 |
Utley; David S. ; et
al. |
January 8, 2009 |
Method and Apparatus for Ablation of Benign, Pre-Cancerous and
Early Cancerous Lesions That Originate Within the Epithelium and
are Limited to the Mucosal Layer of the Gastrointestinal Tract
Abstract
Devices and methods are provided for ablating areas of the
gastrointestinal tract affected with certain benign, pre-cancerous,
or early cancerous lesions that originate within the epithelium and
are limited to the mucosal layer of the gastrointestinal tract
wall. Examples of such lesions include benign conditions such as
cervical inlet patch (ectopic gastric mucosa in the upper
esophagus), as well as pre-cancerous and cancerous conditions such
as intestinal metaplasia/intra-epithelial neoplasia/early cancer of
the stomach, squamous intra-epithelial neoplasia and early cancer
of the esophagus, oral and pharyngeal leukoplakia, flat colonic
polyps, anal intra-epithelial neoplasia (AIN), and early cancers of
the anal canal. Ablation, as provided the invention, commences at
the epithelial layer of the gastrointestinal wall and penetrates
deeper into the gastrointestinal wall in a controlled manner to
achieve a successful patient outcome, the latter of which is
defined generally as eradication of the targeted lesion, and/or a
change in the targeted lesion to prevent or forestall patient
morbidity. Embodiments of the device include an ablational
electrode array that spans 360 degrees and an array that spans an
arc of less than 360 degrees.
Inventors: |
Utley; David S.; (Redwood
City, CA) ; Wallace; Michael P.; (Pleasanton,
CA) |
Correspondence
Address: |
SHAY GLENN LLP
2755 CAMPUS DRIVE, SUITE 210
SAN MATEO
CA
94403
US
|
Family ID: |
40222051 |
Appl. No.: |
12/168042 |
Filed: |
July 3, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60958562 |
Jul 6, 2007 |
|
|
|
60958566 |
Jul 6, 2007 |
|
|
|
Current U.S.
Class: |
606/41 |
Current CPC
Class: |
A61B 18/02 20130101;
A61B 2018/00482 20130101; A61B 2018/00642 20130101; A61B 2090/064
20160201; A61B 2018/00702 20130101; A61B 2018/00875 20130101; A61B
18/1492 20130101; A61B 2018/1497 20130101; A61B 2018/00791
20130101; A61B 2018/00779 20130101; A61B 2018/0016 20130101; A61B
2018/1467 20130101; A61B 2018/00291 20130101; A61B 18/18 20130101;
A61B 2018/00285 20130101; A61B 2018/044 20130101; A61B 2218/007
20130101 |
Class at
Publication: |
606/41 |
International
Class: |
A61B 18/14 20060101
A61B018/14 |
Claims
1. A method of providing ablation based therapy in a target area
having a cervical inlet patch within a portion of the proximal
esophagus, comprising: manipulating a portion of the proximal
esophagus to expose the target area; deploying an ablation device
into contact with the target area; delivering ablative energy to a
tissue surface in the target area; and controlling the delivery of
ablative energy to the tissue surface and layers of the target
area.
2. The method of claim 1, the manipulating step further comprising:
identifying a cervical inlet patch within the target area.
3. The method of claim 1, further comprising: continuing the
manipulating step to expose the target area during the delivering
and controlling steps.
4. The method of claim 1, further comprising: removing debris from
the target area after the controlling step.
5. The method of claim 1, further comprising: removing debris from
the target area after performing the controlling step more than
once.
6. The method of claim 1 wherein the controlling step delivers an
energy density within the range of 10-15 J/cm.sup.2.
7. The method of claim 1 wherein the delivering ablative energy
step comprises delivering ablative energy without an electrode
structure penetrating tissue in the target area.
8. The method of claim 1, the controlling step further comprising:
delivering sufficient ablative energy to achieve ablation in one
fraction of the tissue target surface and delivering insufficient
ablative energy to achieve ablation to another fraction of the
target tissue surface.
9. The method of claim 1, the controlling step further comprising:
controlling the delivery of ablative energy within the target
tissue surface to provide sufficient treatment to achieve ablation
within the cercal inlet patch and yet provide insufficient energy
to other tissue layers beneath the cervical inlet patch.
10. The method of claim 1 wherein controlling the delivery of
ablative energy across the surface and into tissue layers in the
target area is such that some fraction of the tissue volume is
ablated and another fraction of the tissue volume is not
ablated.
11. The method of claim 2 wherein controlling the delivery of
energy into target tissue layers consists of ablating a fraction of
tissue in the epithelial layer of the cervical inlet patch.
12. The method of claim 2 wherein controlling the delivery of
energy into target tissue layers consists of ablating a fraction of
tissue in the epithelial layer and the lamina propria of the
cervical inlet patch.
13. The method of claim 2 wherein controlling the delivery of
energy into the tissue layers consists of ablating a fraction of
cervical inlet patch tissue in the epithelial layer, the lamina
propria, and the muscularis mucosae.
14. The method of claim 2 wherein controlling the delivery of
energy into tissue layers consists of ablating a fraction of
cervical inlet patch tissue in the epithelial layer, the lamina
propria, the muscularis mucosae, and the submucosa.
15. The method of claim 1, the delivering energy step further
comprising: delivering energy in an ablation pattern configured to
conform to a cervical inlet patch.
16. The method of claim 1, further comprising: evaluating the
target area after the delivering energy step.
17. The method of claim 1, the controlling step further comprising:
adjusting the controlling step based on a feedback control of the
energy delivery to provide any of a specific power, a power
density, an energy level, an energy density, a circuit impedance,
target tissue temperature, a number of applications of energy, or a
pressure of application against the tissue.
18. The method of claim 1, the deploying step further comprising:
moving the ablation structure into therapeutic contact with the
target area prior to the delivering energy step.
19. The method of claim 18, the moving step further comprising:
expanding an expandable member to enhance the therapeutic contact
with the target tissue.
20. The method of claim 18, the moving step further comprising:
operating a deflection mechanism to enhance the therapeutic contact
with the target tissue.
21. A method of providing ablation based therapy to a target area
in a stomach having a region containing abnormal gastric tissue,
within the target area, comprising: manipulating a portion of the
stomach to expose the target area; deploying an ablation device
into contact with the target area; delivering ablative energy to a
tissue surface in the target area; and controlling the delivery of
ablative energy to the tissue surface and layers of the target
area.
22. The method of claim 21, the manipulating step further
comprising: identifying the region of abnormal gastric tissue
within the target area after the manipulating step.
23. The method of claim 21, further comprising: continuing the
manipulating step to expose the target area during the delivering
and controlling steps.
24. The method of claim 21, further comprising: removing debris
from the target area after the controlling step.
25. The method of claim 21, further comprising: removing debris
from the target area after performing the controlling step more
than once.
26. The method of claim 21 wherein the controlling step delivers an
energy density of more than 10 J/cm.sup.2 or higher.
27. The method of claim 21 wherein the delivering ablative energy
step comprises delivering ablative energy without an electrode
structure penetrating tissue in the target area.
28. The method of claim 21, the controlling step further
comprising: delivering sufficient ablative energy to achieve
ablation in one fraction of the tissue target surface and
delivering insufficient ablative energy to achieve ablation to
another fraction of the target tissue surface.
29. The method of claim 21, the controlling step further
comprising: controlling the delivery of ablative energy from the
target tissue surface with sufficient energy to achieve ablation
within the region of abnormal gastric tissue within the target area
and insufficient energy is delivered to other target tissue layers
beneath the region of abnormal gastric tissue within the target
area.
30. The method of claim 21 wherein controlling the delivery of
ablative energy across the surface and into tissue layers in the
target area is such that some fraction of the tissue volume is
ablated and another fraction of the tissue volume is not
ablated.
31. The method of claim 22 wherein controlling the delivery of
energy into target tissue layers consists of ablating a fraction of
tissue in the epithelial layer of the region of abnormal gastric
tissue within the target area.
32. The method of claim 22 wherein controlling the delivery of
energy into target tissue layers consists of ablating a fraction of
tissue in the epithelial layer and the lamina propria of the region
of abnormal gastric tissue within the target area.
33. The method of claim 22 wherein controlling the delivery of
energy into the tissue layers consists of ablating a fraction of
the region of abnormal gastric tissue within the target area tissue
in the epithelial layer, the lamina propria, and the muscularis
mucosae.
34. The method of claim 22 wherein controlling the delivery of
energy into tissue layers consists of ablating a fraction of
abnormal gastric tissue within the target area in the epithelial
layer, the lamina propria, the muscularis mucosae, and the
submucosa.
35. The method of claim 21, the delivering energy step further
comprising: delivering energy in an ablation pattern configured to
conform to the region of abnormal gastric tissue within the target
area.
36. The method of claim 21, further comprising: evaluating the
target area after the delivering energy step.
37. The method of claim 21, the controlling step further
comprising: adjusting the controlling step based on a feedback
control of the energy delivery to provide any of a specific power,
a power density, an energy level, an energy density, a circuit
impedance, target tissue temperature, a number of applications of
energy, or a pressure of application against the tissue.
38. The method of claim 21, the advancing step further comprising:
moving the ablation structure into therapeutic contact with the
target area prior to the delivering energy step.
39. The method of claim 38, the moving step further comprising:
expanding an expandable member to enhance the therapeutic contact
with the target tissue.
40. The method of claim 38, the moving step further comprising:
operating a deflection mechanism to enhance the therapeutic contact
with the target tissue.
41. A method of providing ablation based therapy to a target area
in an esophagus having a region of a squamous intra-epithelial
neoplasia and early cancer of the esophagus, hereafter referred to
as abnormal esophageal tissue, within the target area, comprising:
identifying the region of a abnormal esophageal tissue within the
target area; advancing an ablation device into contact with the
target area; delivering ablativeenergy to a tissue surface in the
target area; and controlling the delivery of ablative energy to the
tissue surface and layers of the target area.
42. The method of claim 41 the delivering step further comprising:
delivering energy nearly circumferentially about the esophagus to a
region of abnormal esophageal tissue within a nearly
circumferential target area in the esophagus.
43. The method of claim 41 wherein delivering energy from the
ablation structure includes delivering energy less than
circumferentially about the esophagus to a region of a squamous
intra-epithelial neoplasia within a less than circumferential
target area in the esophagus.
44. The method of claim 41, further comprising: removing debris
from the target area after the controlling step.
45. The method of claim 41, further comprising: removing debris
from the target area after performing the controlling step more
than once.
46. The method of claim 41 wherein the controlling step delivers a
power density in the range of 10 to 15 J/cm.sup.2.
47. The method of claim 41 wherein the delivering ablative energy
step comprises delivering ablative energy without an electrode
structure penetrating tissue in the target area.
48. The method of claim 41, the controlling step further
comprising: delivering sufficient ablative energy to achieve
ablation in one fraction of the tissue target surface and
delivering insufficient ablative energy to achieve ablation to
another fraction of the target tissue surface.
49. The method of claim 41, the controlling step further
comprising: controlling the delivery of ablative energy from the
target tissue surface with sufficient energy to achieve ablation
within the region of a abnormal esophageal tissue in the target
area and insufficient energy is delivered to other target tissue
layers beneath the region of abnormal esophageal tissue within the
target area.
50. The method of claim 41 wherein controlling the delivery of
ablative energy across the surface and into tissue layers in the
target area is such that some fraction of the tissue volume is
ablated and another fraction of the tissue volume is not
ablated.
51. The method of claim 42 wherein controlling the delivery of
energy into target tissue layers consists of ablating a fraction of
tissue in the epithelial layer of the region of abnormal esophageal
tissue within the target area.
52. The method of claim 42 wherein controlling the delivery of
energy into target tissue layers consists of ablating a fraction of
tissue in the epithelial layer and the lamina propria of the region
of abnormal esophageal tissue within the target area.
53. The method of claim 42 wherein controlling the delivery of
energy into the tissue layers consists of ablating a fraction of
the region of abnormal esophageal tissue within the target area
tissue in the epithelial layer, the lamina propria, and the
muscularis mucosae.
54. The method of claim 42 wherein controlling the delivery of
energy into tissue layers consists of ablating a fraction of
abnormal esophageal tissue within the target area in the epithelial
layer, the lamina propria, the muscularis mucosae, and the
submucosa.
55. The method of claim 41, the delivering energy step further
comprising: delivering energy in an ablation pattern configured to
conform to the region of abnormal esophageal tissue within the
target area.
56. The method of claim 41, further comprising: evaluating the
target area after the delivering energy step.
57. The method of claim 41, the controlling step further
comprising: adjusting the controlling step based on a feedback
control of the energy delivery to provide any of a specific power,
a power density, an energy level, an energy density, a circuit
impedance, target tissue temperature, a number of applications of
energy, or a pressure of application against the tissue.
58. The method of claim 41, the advancing step further comprising:
moving the ablation structure into therapeutic contact with the
target area prior to the delivering energy step.
59. The method of claim 58, the moving step further comprising:
expanding an expandable member to enhance the therapeutic contact
with the target tissue.
60. The method of claim 58, the moving step further comprising:
operating a deflection mechanism to enhance the therapeutic contact
with the target tissue.
61. A method of providing ablation based therapy in a target area
having a region of leukoplakia within the oral and/or pharyngeal
cavity, comprising: manipulating a portion of the oral and
pharyngeal cavity to expose the target area; deploying an ablation
device into contact with the target area; delivering ablative
energy to a tissue surface in the target area; and controlling the
delivery of ablative energy to the tissue surface and layers of the
target area.
62. The method of claim 61, the manipulating step further
comprising: identifying a region of leukoplakia within the target
area.
63. The method of claim 61, further comprising: continuing the
manipulating step to expose the target area during the delivering
and controlling steps.
64. The method of claim 61, further comprising: removing debris
from the target area after the controlling step 65.
65. The method of claim 61, further comprising: removing debris
from the target area after performing the controlling step more
than once.
66. The method of claim 61 wherein the controlling step delivers a
power density within the range of 10-15 J/cm.sup.2.
67. The method of claim 61 wherein the delivering ablative energy
step comprises delivering ablative energy without an electrode
structure penetrating tissue in the target area.
68. The method of claim 61, the controlling step further
comprising: delivering sufficient ablative energy to achieve
ablation in one fraction of the tissue target surface and
delivering insufficient ablative energy to achieve ablation to
another fraction of the target tissue surface.
69. The method of claim 61, the controlling step further
comprising: controlling the delivery of ablativeenergy from the
target tissue surface with sufficient energy to achieve ablation
within the region of leukoplakia and insufficient energy is
delivered to other target tissue layers beneath the region of
leukoplakia.
70. The method of claim 61 wherein controlling the delivery of
ablative energy across the surface and into tissue layers in the
target area is such that some fraction of the tissue volume is
ablated and another fraction of the tissue volume is not
ablated.
71. The method of claim 62 wherein controlling the delivery of
energy into target tissue layers consists of ablating a fraction of
tissue in the epithelial layer of the region of leukoplakia.
72. The method of claim 62 wherein controlling the delivery of
energy into target tissue layers consists of ablating a fraction of
tissue in the epithelial layer and the lamina propria of the region
of leukoplakia.
73. The method of claim 62 wherein controlling the delivery of
energy into the tissue layers consists of ablating a fraction of
the region of leukoplakia tissue in the epithelial layer, the
lamina propria, and the muscularis mucosae.
74. The method of claim 62 wherein controlling the delivery of
energy into tissue layers consists of ablating a fraction of the
region of leukoplakia tissue in the epithelial layer, the lamina
propria, the muscularis mucosae, and the submucosa.
75. The method of claim 61, the delivering energy step further
comprising: delivering energy in an ablation pattern configured to
conform to a region of leukoplakia.
76. The method of claim 61, further comprising: evaluating the
target area after the delivering energy step.
77. The method of claim 61, the controlling step further
comprising: adjusting the controlling step based on a feedback
control of the energy delivery to provide any of a specific power,
a power density, an energy level, an energy density, a circuit
impedance, target tissue temperature, a number of applications of
energy, or a pressure of application against the tissue.
78. The method of claim 61, the deployment step further comprising:
moving the ablation structure into therapeutic contact with the
target area prior to the delivering energy step.
79. The method of claim 78, the moving step further comprising:
expanding an expandable member to enhance the therapeutic contact
with the target tissue.
80. The method of claim 78, the moving step further comprising:
operating a deflection mechanism to enhance the therapeutic contact
with the target tissue.
81. The method of claim 78 the moving step further comprising:
deforming the ablation structure to at least partially conform to
the region of leukoplakia.
82. The method of claim 61 further comprising: placing the ablation
structure on a finger of a user prior to the advancing step and
keeping the ablation structure on the finger of the user during the
delivering an controlling steps.
83. The method of claim 61 wherein the deploying step is performed
using a hand held ablation device under direct visualization.
84. A method of providing ablation based therapy to a target area
in a colon and/or rectum having a region of one or more flat-type
polyps within the target area, comprising: manipulating a portion
of the colon to expose the target area; deploying an ablation
device into contact with the target area; delivering ablative
energy to a tissue surface in the target area; and controlling the
delivery of ablative energy to the tissue surface and layers of the
target area.
85. The method of claim 84, the manipulating step further
comprising: identifying the region of one or more flat-type polyps
within the target area after the manipulating step.
86. The method of claim 84, further comprising: continuing the
manipulating step to expose the target area during the delivering
and controlling steps.
87. The method of claim 84, further comprising: removing debris
from the target area after the controlling step.
88. The method of claim 84, further comprising: removing debris
from the target area after performing the controlling step more
than once.
89. The method of claim 84 wherein the controlling step delivers a
power density of 10 J/cm2 or greater.
90. The method of claim 84 wherein the delivering ablative energy
step comprises delivering ablative energy without an electrode
structure penetrating tissue in the target area.
91. The method of claim 84, the controlling step further
comprising: delivering sufficient ablative energy to achieve
ablation in one fraction of the tissue target surface and
delivering insufficient ablative energy to achieve ablation to
another fraction of the target tissue surface.
92. The method of claim 84, the controlling step further
comprising: controlling the delivery of ablative energy from the
target tissue surface with sufficient energy to achieve ablation
within the region of one or more flat-type polyps within the target
area and insufficient energy is delivered to other target tissue
layers beneath the region of one or more flat-type polyps within
the target area.
93. The method of claim 84 wherein controlling the delivery of
ablative energy across the surface and into tissue layers in the
target area is such that some fraction of the tissue volume is
ablated and another fraction of the tissue volume is not
ablated.
94. The method of claim 85 wherein controlling the delivery of
energy into target tissue layers consists of ablating a fraction of
tissue in the epithelial layer of the region of one or more
flat-type polyps within the target area.
95. The method of claim 85 wherein controlling the delivery of
energy into target tissue layers consists of ablating a fraction of
tissue in the epithelial layer and the lamina propria of the region
of one or more flat-type polyps within the target area.
96. The method of claim 85 wherein controlling the delivery of
energy into the tissue layers consists of ablating a fraction of
the region of one or more flat-type polyps within the target area
tissue in the epithelial layer, the lamina propria, and the
muscularis mucosae.
97. The method of claim 85 wherein controlling the delivery of
energy into tissue layers consists of ablating a fraction of the
region of one or more flat-type polyps within the target area in
the epithelial layer, the lamina propria, the muscularis mucosae,
and the submucosa.
98. The method of claim 84, the delivering energy step further
comprising: delivering energy in an ablation pattern configured to
conform to the region of one or more flat-type polyps within the
target area.
99. The method of claim 84, further comprising: evaluating the
target area after the delivering energy step.
100. The method of claim 84, the controlling step further
comprising: adjusting the controlling step based on a feedback
control of the energy delivery to provide any of a specific power,
a power density, an energy level, an energy density, a circuit
impedance, target tissue temperature, a number of applications of
energy, or a pressure of application against the tissue.
101. The method of claim 84, the advancing step further comprising:
moving the ablation structure into therapeutic contact with the
target area prior to the delivering energy step.
102. The method of claim 101, the moving step further comprising:
expanding an expandable member to enhance the therapeutic contact
with the target tissue.
103. The method of claim 101, the moving step further comprising:
operating a deflection mechanism to enhance the therapeutic contact
with the target tissue.
104. The method of claim 84 wherein the delivering step comprises
delivering ablative energy to a tissue surface containing residual
flat-type polyp tissue in the target area where a partial or
complete polypectomy has been performed.
105. A method of providing ablation based therapy in an anal target
area having a region of abnormal anal tissue, comprising:
manipulating a portion of the anal canal to expose the target area;
deploying an ablation device into contact with the target area;
delivering ablative energy to a tissue surface in the target area;
and controlling the delivery of ablative energy to the tissue
surface and layers of the target area.
106. The method of claim 105, the manipulating step further
comprising: identifying a region of abnormal anal tissue within the
target area.
107. The method of claim 105, further comprising: continuing the
manipulating step to expose the target area during the delivering
and controlling steps.
108. The method of claim 105, further comprising: removing debris
from the target area after the controlling step.
109. The method of claim 105, further comprising: removing debris
from the target area after performing the controlling step more
than once.
110. The method of claim 105 wherein the controlling step delivers
a power density within the range of 10-15 J/cm2.
111. The method of claim 105 wherein the delivering ablative energy
step comprises delivering ablative energy without an electrode
structure penetrating tissue in the target area.
112. The method of claim 105, the controlling step further
comprising: delivering sufficient ablativeenergy to achieve
ablation in one fraction of the tissue target surface and
delivering insufficient ablative energy to achieve ablation to
another fraction of the target tissue surface.
113. The method of claim 105, the controlling step further
comprising: controlling the delivery of ablative energy from the
target tissue surface with sufficient energy to achieve ablation
within the region of abnormal anal tissue and insufficient energy
is delivered to other target tissue layers beneath the region of
abnormal anal tissue.
114. The method of claim 105 wherein controlling the delivery of
ablative energy across the surface and into tissue layers in the
target area is such that some fraction of the tissue volume is
ablated and another fraction of the tissue volume is not
ablated.
115. The method of claim 106 wherein controlling the delivery of
energy into target tissue layers consists of ablating a fraction of
tissue in the epithelial layer of the region of abnormal anal
tissue.
116. The method of claim 106 wherein controlling the delivery of
energy into target tissue layers consists of ablating a fraction of
tissue in the epithelial layer and the lamina propria of the region
of abnormal anal tissue.
117. The method of claim 106 wherein controlling the delivery of
energy into the tissue layers consists of ablating a fraction of
the region of abnormal anal tissue in the epithelial layer, the
lamina propria, and the muscularis mucosae.
118. The method of claim 106 wherein controlling the delivery of
energy into tissue layers consists of ablating a fraction of the
region of abnormal anal tissue in the epithelial layer, the lamina
propria, the muscularis mucosae, and the submucosa.
119. The method of claim 105, the delivering energy step further
comprising: delivering energy in an ablation pattern configured to
conform to a region of intraepithelial neoplasia.
120. The method of claim 105, further comprising: evaluating the
target area after the delivering energy step.
121. The method of claim 105, the controlling step further
comprising: adjusting the controlling step based on a feedback
control of the energy delivery to provide any of a of a specific
power, a power density, an energy level, an energy density, a
circuit impedance, target tissue temperature, a number of
applications of energy, or a pressure of application against the
tissue.
122. The method of claim 105, the deployment step further
comprising: moving the ablation structure into therapeutic contact
with the target area prior to the delivering energy step.
123. The method of claim 122, the moving step further comprising:
expanding an expandable member to enhance the therapeutic contact
with the target tissue.
124. The method of claim 122, the moving step further comprising:
operating a deflection mechanism to enhance the therapeutic contact
with the target tissue.
125. The method of claim 122 the moving step further comprising:
deforming the ablation structure to at least partially conform to
the region of abnormal anal tissue.
126. The method of claim 105 further comprising: placing the
ablation structure on a finger of a user prior to the advancing
step and keeping the ablation structure on the finger of the user
during the delivering an controlling steps.
127. The method of claim 105 wherein the deploying step is
performed using a hand held ablation device under direct
visualization.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Patent Application No. 60/958,562 "Non-Barrett's Mucosal Ablation
Disease Targets," by Utley and Wallace, as filed on Jul. 6, 2007,
and of U.S. Provisional Application No. 60/958,566, entitled
"Non-Barrett's Mucosal Ablation Disease Targets" by Utley et al.,
as filed on Jul. 6, 2007.
[0002] This application also incorporates herein by reference
commonly assigned U.S. patent application Ser. No. 10/370,645
entitled "Method of Treating Abnormal Tissue in the Human
Esophagus," filed on Feb. 19, 2003, and published as US
2003/0158550 on Aug. 21, 2003, and U.S. patent application Ser. No.
11/286,444 entitled "Precision Ablating Method," filed on Nov. 23,
2005, and published as US 2007/0118106 on May 24, 2007. Further,
each of the following commonly assigned United States patent
applications are incorporated herein by reference in its entirety:
patent application Ser. No. 10/291,862 titled "Systems and Methods
for Treating Obesity and Other Gastrointestinal Conditions," patent
application Ser. No. 10/370,645 titled "Method of Treating Abnormal
Tissue In The Human Esophagus," patent application Ser. No.
11/286,257 titled "Precision Ablating Device," patent application
Ser. No. 11/275,244 titled "Auto-Aligning Ablating Device and
Method of Use," patent application Ser. No. 11/286,444 titled
"Precision Ablating Device," patent application Ser. No. 11/420,712
titled "System for Tissue Ablation," patent application Ser. No.
11/420,714 titled "Method for Cryogenic Tissue Ablation," patent
application Ser. No. 11/420,719 titled "Method for Vacuum-Assisted
Tissue Ablation," patent application Ser. No. 11/420,722 titled
"Method for Tissue Ablation," patent application Ser. No.
11/469,816 titled "Surgical Instruments and Techniques for Treating
Gastro-esophageal Reflux Disease." This application further
incorporates in entirety U.S. patent application Ser. No.
10/291,862 of Utley, filed on Nov. 8, 2002 entitled "Systems and
Methods for Treating Obesity and Other Gastrointestinal
Conditions," and published on May 13, 2004 as US 2004/0089313, and
U.S. Pat. No. 7,326,207 of Edwards, entitled "Surgical Weight
Control Device," which issued on Feb. 5, 2008. This application
further incorporates in entirety U.S. patent application Ser. No.
12/114,628 of Kelly et al. entitled "Method and Apparatus for
Gastrointestinal Tract Ablation for Treatment of Obesity," as filed
on filed May 2, 2008. This application further incorporates in
entirety U.S. patent application Ser. No. 12/143,404, of Wallace et
al., entitled "Electrical Means to Normalize Ablational Energy
Transmission to a Luminal Tissue Surface of Varying Size," as filed
on Jun. 20, 2008.
INCORPORATION BY REFERENCE
[0003] All publications, patents and patent applications mentioned
in this specification are herein incorporated by reference to the
same extent as if each individual publication, patent or patent
application was specifically and individually indicated to be
incorporated by reference.
FIELD OF THE INVENTION
[0004] The present invention relates to therapeutic devices and
methods for treatment of the gastrointestinal tract affected with
certain benign, pre-cancerous and early cancerous lesions that
originate within the epithelium and are limited to the mucosal
layer of the gastrointestinal tract wall.
BACKGROUND OF THE INVENTION
[0005] There is yet to be an ideal, non-surgical, therapeutic
intervention for certain benign, precancerous and early cancerous
lesions that originate within the epithelium and are limited to the
mucosal layer of the gastrointestinal tract wall. Examples of such
lesions are illustrated schematically in FIG. 1 and include benign
(non-cancerous) conditions such as cervical inlet patch (ectopic
gastric mucosa in the upper esophagus), as well as pre-cancerous
and cancerous conditions such as intestinal
metaplasia/intra-epithelial neoplasia/early cancer of the stomach,
squamous intra-epithelial neoplasia and early cancer of the
esophagus, oral and pharyngeal leukoplakia, flat colonic polyps,
anal intra-epithelial neoplasia (AIN) and early cancers of the anal
canal. These benign, precancerous and cancerous lesions of the
gastrointestinal tract that originate within the epithelium are
potentially amenable to curative endoscopic therapy, as described
herein, thus avoiding major surgery. Certain non-surgical therapies
have been attempted for treating these lesions, however, they have
been limited in safety, technical feasibility, and
effectiveness.
[0006] A common denominator for these lesions is that they
originate within the epithelium, the most superficial layer of the
gastrointestinal tract wall. For the benign and pre-cancerous
lesions, the only layer affected by the lesion is the epithelium,
making these lesions highly amenable to an optimized endoscopic
therapy, as disclosed herein. For certain other types of lesions,
such as early stage cancerous lesions that are limited to the
mucosal layer (epithelium, lamina propria, and muscularis mucosae),
curative therapy is also possible using an optimized therapy, as
disclosed herein.
[0007] While these lesions have the described common denominator of
originating within the epithelial layer, an important
differentiating feature is that they occur in different regions of
the gastrointestinal tract which have different anatomic and
geometric configurations, thus mandating different devices and
methods to achieve effective treatment.
[0008] A further differentiating feature for these lesions is that
they each have diverse etiology, lesion characteristics (depth, for
example), and propensity to cause patient morbidity and mortality.
Cervical inlet patch of the esophagus is an embryological remnant
of gastric tissue that resides high in the esophagus. Often, this
lesion produces stomach acid, thereby causing discomfort in the
esophagus. Intestinal metaplasia, intra-epithelial neoplasia, and
early cancer of the stomach are a spectrum of progressive tissue
changes towards invasive gastric cancer, a world-wide epidemic.
These changes may be caused by diet, smoking, and infection.
Squamous intra-epithelial neoplasia and early cancer of the
esophagus is related to diet, environmental fungus, smoke exposure,
and alcohol use, and is also a world-wide epidemic. Oral and
pharyngeal leukoplakia is an epithelial pre-cancerous change that
leads to head and neck squamous cell cancer, and is due to smoking
and alcohol use.
[0009] Flat polyps of the colon and rectum are precursors to more
advanced polypoid lesions and invasive cancer. FIGS. 2A, 2B and 2C
are schematic side views of colorectal polyps 52 or adenomas
referred to collectively herein as flat type polyps. The exemplary
polyps are stalked (FIG. 2A), pedunculated (FIG. 2B) and sessile
(FIG. 2C). Anal intra-epithelial neoplasia and early cancer of the
anal canal occurs as a result of human papilloma infection
predominantly in men who have sex with men.
[0010] There remains a need for improved non-surgical, therapeutic
intervention for certain benign, precancerous and early cancerous
lesions that originate within the epithelium and are limited to the
mucosal layer of the gastrointestinal tract wall.
SUMMARY OF THE INVENTION
[0011] Provided herein by the invention are methods for ablation
therapy directed to benign, pre-cancerous and early cancerous
lesions of the gastrointestinal tract that originate within the
epithelium and are contained within the mucosal layer. Such lesions
may include, by way of example, a cervical inlet patch within a
portion of the proximal esophagus, abnormal gastric tissue (such as
intestinal metaplasia, intraepithelial neoplasia, and early cancer
of the stomach), abnormal esophageal tissue (such as squamous
intraepithelial neoplasia and early cancer), leukoplakia within the
oral or pharyngeal cavity, polyps in the colon or rectum, anal
lesions (such as anal intraepithelial neoplasis and early anal
cancer). These lesions, in spite of differences in particulars of
origin, developmental stage, and morphology, for the purpose of
this summary, will be collectively referred to as lesions within
the mucosal layer of the gastrointestinal tract.
[0012] Embodiments of the method of ablation therapy directed to a
target area of a lesion within the mucosal layer of the
gastrointestinal traction include manipulating a portion of the
gastrointestinal tract near the lesion in order to expose the
target area, deploying or advancing an ablation device into contact
with the target area, delivering ablative energy to a tissue
surface in the target area; and controlling the delivery of
ablative energy to the tissue surface and into tissue layers of the
target area.
[0013] The method may further include, in addition to or in
conjunction with the manipulating step, any of identifying the
lesion, identifying a target area within the lesion, or
manipulating the lesion site or target area in order to expose the
target area during the steps of delivering of ablative energy and
controlling the delivery of ablative energy.
[0014] The method may further include removing debris from the
target area after the delivering and controlling steps, and it may
further include removing debris from the target area after
performing the controlling step more than once.
[0015] The step of controlling the delivery of energy may include
controlling the energy density such that it is in the range of
about 10- to about 15 J/cm.sup.2.
[0016] The step of delivering energy may include delivering
ablative energy without an electrode structure penetrating tissue
in the target area.
[0017] The step of controlling the delivery of energy may include
delivering sufficient ablative energy to achieve ablation in one
fraction of the lesion's tissue target surface and delivering
insufficient ablative energy to achieve ablation to another
fraction of the lesion's target tissue surface. The step of
controlling the delivery of energy may also include controlling the
delivery of ablative energy to the lesion's target tissue surface
to provide sufficient treatment to achieve ablation within tissue
layers near the surface of the target area and yet provide
insufficient energy to deeper tissue layers beneath the target area
of the lesion.
[0018] In another aspect, controlling the delivery of ablative
energy across the surface and into tissue layers in the lesion's
target area is such that some fraction of the tissue volume is
ablated and another fraction of the tissue volume is not ablated.
Thus, with more specific regard to the tissue layers of the lesion,
controlling the delivery of energy into target tissue layers may
variously consist of ablating a fraction of tissue in the
epithelial layer of the cervical inlet patch, ablating a fraction
of tissue in the epithelial layer and the lamina propria of the
cervical inlet patch, ablating a fraction of cervical inlet patch
tissue in the epithelial layer, the lamina propria, and the
muscularis mucosae, or ablating a fraction of cervical inlet patch
tissue in the epithelial layer, the lamina propria, the muscularis
mucosae, and the submucosa.
[0019] In some embodiments of the method, the delivering energy
step may further include delivering energy in an ablation pattern
that conforms to the specific size and conformational features of
the lesion, such size and conformation being particular to each
lesion addressed by the method, such as a cervical inlet patch
within a portion of the proximal esophagus, an abnormal gastric
tissue (such as intestinal metaplasia, intra-epithelial neoplasia,
and early cancer of the stomach), an abnormal esophageal tissue
(such as squamous intra-epithelial neoplasia and early cancer), a
site of leukoplakia within the oral or pharyngeal cavity, polyps in
the colon or rectum, and anal lesions (such as anal intraepithelial
neoplasis and early anal cancer). Such particulars of lesion size
and conformation may include, for example, lesions being flat, as
oral leukoplakia are, or stalked or pedunculated as some colorectal
polyps may be, or particulars such as the size and available
capacity for instrument maneuverability as in the stomach, or the
relative accessibility of the anus or oral cavity.
[0020] Some embodiments of the method may farther include
evaluating the target area of the lesion at a point in time after
the delivering energy step, in order to determine the status of the
area. The evaluating step may occur in close time proximity after
the delivery of energy, to evaluate the immediate post-treatment
status of the site. In various embodiments, the evaluating step
occurs at least one day after the delivery of energy.
[0021] In some embodiments of the method, the controlling step may
further include adjusting the energy delivery to provide any of a
specific power, a power density, an energy level, an energy
density, a circuit impedance, target tissue temperature, a number
of applications of energy, or a pressure of application against the
tissue.
[0022] In some embodiments of the method, the deploying or
advancing step may further include moving the ablation structure
into therapeutic contact with the target area prior to the
delivering energy step. In various embodiments, the moving step may
include expanding an expandable member to enhance the therapeutic
contact with the target tissue, or operating a deflection mechanism
to enhance the therapeutic contact with the target tissue.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] FIG. 1 provides a view of the gastrointestinal tract and the
location of sites of abnormal tissue that may be targeted for
ablation, as provided by systems and methods of ablation as
described herein.
[0024] FIGS. 2A, 2B and 2C are schematic side views of colorectal
polyps or adenomas referred to collectively as flat type polyps.
The exemplary polyps are stalked, pedunculated and sessile,
respectively.
[0025] FIG. 3 is a flow diagram depicting an overview of the
method, wherein an appropriate site for ablational treatment of a
gastrointestinal tract having one or more abnormal lesions is
determined, the level of ablational therapy is determined, and at
least preliminary information is gained regarding localization, and
clinical judgment is exercised as to which embodiment of the
invention is preferable.
[0026] FIG. 4 is a flow diagram depicting the method after the site
of ablation of a portion of the gastrointestinal tract has been
localized and a choice has been made regarding the preferred
ablational device. The method includes an evaluation of the site,
including particulars of location, stage, determination of the
number of sites, and the dimensions. The method continues with
insertion of the instrument and its movement to the locale of the
ablational target tissue, the more refined movement of the
ablational structure that create a therapeutically effective
contact, the emission of ablational radiation and then
post-treatment evaluation.
[0027] FIG. 5 is a view of an embodiment of an ablative device with
a fully circumferential operating radius.
[0028] FIG. 6 is a view of an embodiment of an ablative device with
a fully circumferential operating radius, with a balloon member in
an expanded configuration.
[0029] FIGS. 7A-7C show the electrode patterns of the device of
FIG. 5.
[0030] FIGS. 8A-8D show electrode patterns that may be used with
embodiments of the ablative device with a fully circumferential
operating radius, or with any device embodiments described
herein.
[0031] FIG. 9 is a view of the ablation device of the invention
with a partially circumferential operating radius.
[0032] FIG. 10 is an end view of the ablation device embodiment of
FIG. 9.
[0033] FIG. 11 is an end view of the device of FIG. 9 in an
expanded configuration.
[0034] FIGS. 12, 13, and 14 are end views of the device of FIG. 9
in alternative expanded configurations.
[0035] FIG. 15 is a view of the ablation device of the invention in
an unexpanded configuration.
[0036] FIG. 16 is a view of the ablation device of the invention in
an expanded configuration.
[0037] FIGS. 17 and 18 are end views of the device in an expanded
configuration.
[0038] FIG. 19A is a view of the ablation device of the invention
showing a deflection member feature.
[0039] FIG. 19B is a view of the ablation device of the invention
showing an alternative deflection member wherein the device is in
an expanded configuration.
[0040] FIG. 20 is a view of device shown in FIG. 19B wherein the
deflection member is in an unexpanded configuration.
[0041] FIG. 21 is an end view of the device in an unexpanded
configuration.
[0042] FIG. 22 is an end view of the device shown in FIG. 21 in an
expanded configuration.
[0043] FIG. 23 is a view of the ablation device of the invention
showing a pivoting ablation structure feature.
[0044] FIG. 24 is an illustration of the ablation device of the
invention combined with an endoscope system.
[0045] FIG. 25 is a schematic of view of a section through the wall
of a representative organ of the gastrointestinal tract.
[0046] FIG. 26 is a view of the ablation device of the invention
including an elongated sheath feature.
[0047] FIG. 27 is a view of the device wherein an elongated sheath
feature is optically transmissive.
[0048] FIG. 28 is an enlarged view of the optically transmissive
feature of the device.
[0049] FIG. 29 is a cross sectional view of the optically
transmissive sheath feature of the device shown in FIGS. 27 and
28.
[0050] FIG. 30 is a view of the device including an alternative
optically transmissive sheath feature and an inflation member
feature in an expanded configuration.
[0051] FIG. 31 is an illustration of the ablation device of FIG. 30
positioned within an esophagus.
[0052] FIG. 32 is a view of the ablation device of the invention
including a slit sheath feature.
[0053] FIG. 33A is an end view of a slit sheath feature of the
device wherein the sheath is in an unexpanded configuration.
[0054] FIG. 33B is an end view of a slit sheath feature of the
device and an endoscope wherein the sheath is in an expanded
configuration.
[0055] FIG. 34A is a cross sectional view of the device positioned
within an endoscope internal working channel wherein an inflatable
member feature is in an unexpanded position.
[0056] FIG. 34B is a view of the device shown in FIG. 34A wherein
the inflatable member feature is in an expanded position.
[0057] FIG. 35A is a cross sectional view of the device positioned
within an endoscope internal working channel wherein an expandable
member feature is in an unexpanded position.
[0058] FIG. 35B is a view of the device shown in FIG. 35A wherein
the expandable member feature is in an expanded position.
[0059] FIG. 36A is a cross sectional view of the device positioned
within an endoscope internal working channel wherein an alternative
expandable member feature is in an unexpanded position.
[0060] FIG. 36B is a view of the device shown in FIG. 36A wherein
the expandable member feature is in an expanded position.
[0061] FIG. 37 is a view of the ablation device of the invention
including an alternative deflection member.
[0062] FIG. 38 is an illustration of the ablation device of the
invention including an alternative deflection member positioned
within the lumen of an organ of the gastrointestinal tract in a
non-deflected position.
[0063] FIG. 39 is an illustration of the device shown in FIG. 38
wherein the deflection member is in a deflected position.
[0064] FIG. 40 is a cross sectional view of the ablation device of
the invention showing an internal coupling mechanism feature.
[0065] FIG. 41 is a cross sectional view of the ablation device of
the invention showing an alternative internal coupling mechanism
and a rolled sheath feature.
[0066] FIG. 42 is an illustration showing a cross sectional view of
the ablation device of the invention positioned within the lumen of
an organ of the gastrointestinal tract.
[0067] FIG. 43 is an illustration of the ablation-device of the
invention positioned within an esophagus showing a rotational
feature.
[0068] FIG. 44 is an illustration of the ablation device of the
invention positioned within an esophagus showing a rotational
feature combined with an inflation member in an expanded
configuration.
[0069] FIGS. 45A-45C are views of the ablation device of the
invention showing alternative rotational features.
[0070] FIG. 46A is a view of an endoscope.
[0071] FIG. 46B is a view of the ablation device of the invention
including a catheter feature.
[0072] FIG. 46C is a view of a sheath feature of the device.
[0073] FIG. 47 is a view of the ablation device of the invention
including the features shown in FIGS. 46A-46C in an assembly.
[0074] FIGS. 48A-48D show an electrode array with a striped pattern
for a fractional ablation and the ablation patterns on tissue that
can be made from such a pattern.
[0075] FIGS. 49A and 49B show an electrode array with a
concentric-circle pattern for a fractional ablation and the
ablation patterns on tissue that can be made from such a
pattern.
[0076] FIGS. 50A and 50B show an electrode array with a
checkerboard pattern for a fractional ablation and the ablation
patterns on tissue that can be made from such a pattern.
[0077] FIGS. 51A and 51B show an electrode array with a
checkerboard pattern operating in a non-fractional manner and the
ablation pattern on tissue that is made from such an operating
pattern.
[0078] FIGS. 52A and 52B show an electrode array with a
checkerboard pattern operating in a fractional manner and the
ablation pattern on tissue that is made from such an operating
pattern.
[0079] FIGS. 53A and 53B show an electrode array with a striped
pattern of alternating positive and negative electrodes operating
in a non-fractional manner and the ablation patterns on tissue that
can be made from such an operating pattern.
[0080] FIGS. 54A and 54B show an electrode array with a striped
pattern of alternating positive and negative electrodes operating
in a fractional manner and the ablation patterns on tissue that can
be made from such an operating pattern.
[0081] FIG. 55 shows a schematic rendering of a three-dimensional
view of a target region of a radial portion of a gastrointestinal
wall after it has been ablationally treated.
[0082] FIGS. 56A and 56B provide views of an ablational device
(similar to the devices of FIGS. 38 and 39) but including an
ablational surface on a hinge structure or deflecting mechanism
similar to that depicted in FIG. 43, the hinge allowing a free
pivoting movement of the ablational surface between its
longitudinal axis and the longitudinal axis of an endoscope. FIG.
56A shows the device with the ablational surface oriented in
parallel with the endoscope. FIG. 56B shows the device with the
longitudinal axis of the ablational surface oriented at about a
right angle with respect to the longitudinal axis of the
endoscope.
[0083] FIG. 57A-57D provide perspective views of an ablation device
with a 360 degree circumferential ablation surface on an
overlapping electrode support furled around an expandable balloon,
the operative element including a balloon and an electrode support
in an expanded state. FIG. 57A shows the support pulled away from
the balloon to clarify that a portion of the support and an edge is
adherent to the balloon, and another portion and its edge is not
connected to the balloon.
[0084] FIG. 57B shows the operative element of the device with the
non-adherent portion of the support furled around the balloon in a
deployable configuration, the non-adherent portion and its edge
overlapping around the adherent portion.
[0085] FIG. 57C shows the device of FIGS. 57A and 57B with an
optional feature of the operative element, one or more elastic
bands wrapped around the electrode support.
[0086] FIG. 57D shows the device of FIG. 57C in a collapsed state,
with balloon portion being uninflated (or deflated), this being the
state of the device when it is being deployed into a lumen and
being positioned at a target site, as well as the state of the
device after delivering ablation energy and about to be removed
from the lumen.
[0087] FIGS. 58A-58B depict an embodiment of an ablation device
that is adapted to present an ablational surface into a concave or
inwardly tapered target site such as the pylorus. The device
includes an ablational surface circumferentially arranged on the
distal portion of an expandable member, the expandable member
mounted around the distal end of an endoscope. FIG. 58A shows the
device in a deployed configuration.
[0088] FIG. 58B shows the device with the expandable member in an
unexpanded or collapsed state, as would be appropriate for
deployment of the device to a target tapered surface, or as would
be appropriate for removal from the ablational site.
[0089] FIG. 59 is a perspective view of a hand held ablation
therapy device.
[0090] FIG. 60 is a perspective view of a finger-mountable ablation
therapy device.
DETAILED DESCRIPTION
[0091] Aspects of the present invention provide various embodiments
of a therapeutic device and method to treat the disclosed benign,
pre-cancerous and early cancerous lesions that originate within the
epithelium and are limited to the mucosal layer of the
gastrointestinal tract wall. Successful treatment of these lesions
implies a treatment that does not cause excessive patient morbidity
due to over-treatment, excessively deep penetration of the
treatment effect, perforation, bleeding, or other such
complication. A successful treatment, from an efficacy standpoint,
is defined as complete removal of all abnormal tissue, a change in
the abnormal tissue such that it no longer produces symptoms, or
change in the abnormal tissue such that it no longer has the
propensity to develop invasive cancer or that the risk of
developing invasive cancer is more remote or time-delayed.
[0092] Current techniques, excluding the present invention
disclosed herein, for treating these disclosed lesions include
coagulation, mucosal resection, and cryotherapy. These techniques
are limited in the amount of tissue surface area that can be safely
and effectively treated during one or more treatment sessions, due
to specific limitations of the device, technique, and tissue
effects, so wide-spread lesions are not amenable to effective
treatment with these approaches. Further, coagulation and
cryotherapy are limited in their ability to control the depth of
ablation, resulting in under-treatment and over-treatment of
certain areas within the lesion. This non-uniform treatment can
result in persistence of the lesion (under-treatment) or patient
complications (over-treatment). Mucosal resection is a deep
resection technique that removes the entire mucosa and submucosa, a
depth of penetration that is excessive and unnecessary for the
successful treatment of the disclosed lesions. Wide-spread
endoscopic resection can result in significant complications and is
not feasible in most cases.
[0093] To this end, in some the device embodiments disclosed herein
there is a catheter that is either balloon-based or not
balloon-based, and, is either mounted on the end of an endoscope,
passes through a working channel or accessory channel of an
endoscope, passes along side an endoscope, or is hand-held using
direct visualization of the target lesion. Alternatively, the
device may be handheld or worn on one or more fingers. The device
has an energy delivery element, such as an electrical array, on at
least one surface to deliver ablation energy from a source to the
targeted tissue in a manner so that the depth of ablation is
controlled via parameters such as energy density, electrode
pattern, power density, number of applications, and pressure
exerted on the tissue. This configuration allows both successful
treatment of focal lesions as well as successful treatment of more
widespread, diffuse lesions. The catheter is supplied with ablation
energy by an energy generator, connected to the catheter with a
cable. Various alternative ablation devices are illustrated and
described with regard to FIGS. 5 to 60.
[0094] Embodiments of the inventive method includes using the
devices described, in conjunction with an endoscope for
visualization of the lesion in some cases (or for some lesions,
using direct visualization without an endoscope), positioning the
device in one or more locations at the target lesion, deploying the
device so as to make therapeutic contact with the lesion, and
delivering ablative energy one or more times. Treatment parameters
may be such that a uniform level of ablation is achieved in all or
part of the lesion. For example, the entire epithelium can be
removed, without injury to deeper layers of the structure. Another
example is to apply energy in a uniform manner to incur a deeper
injury, including the entire thickness of the mucosa (epithelium,
lanina propria, muscularis mucosae). Yet another example would be
to apply the treatment to include a portion of the submucosa. The
desired depth of ablation and pattern of ablation is predicated
upon the specific lesion being treated.
[0095] One factor for successful treatment of these lesions is
adequate contact of the treatment element with the lesion and the
epithelial surface. In some circumstances, this therapeutic contact
can be achieved using a relatively planar structure mounted on the
end of an endoscope (for lesions in the stomach or esophagus, for
example). In other circumstances involving tubular structures, this
may be achieved with a balloon-mounted treatment element (as in the
proximal esophagus or colon, for example). In other circumstances,
a more complex anatomic and geometric structure must be treated,
requiring the treatment element to be mounted on a conformable
structure, such as a malleable substrate, or alternatively a sponge
(as in lesions located in the oral cavity, pharyngeal space, distal
rectum and anal canal.)
[0096] A number of embodiments of ablation devices are provided
herein, which may be described as having an ablational surface that
spans either a 360-degree circumference, or some fractional portion
of a full circumference around the device. For example, some
devices have an ablational surface that spans about 180 degrees,
and others have an ablational surface that spans about 90 degrees.
Ablation devices may be mounted on an instrument such as a
catheter, endoscope or colonscope. Some ablation device embodiments
are hand held or worn on one or more fingers or a glove worn by a
user. The ablation devices may be used to accomplish the method
treatment described herein.
[0097] The various alternative device embodiments may be
categorized based on the size of the ablation device and the
configuration of the ablational surface. Some device embodiments
have an ablation surface that spans a complete 360 degree
circumference that is expandable through the use of an expandable
member included in the device internal to the ablational surface.
Several such representative embodiments are shown and further
described below (FIGS. 6, 57, and 58) and described further below.
Embodiments of the fully circumferential ablational surface are
typically cylindrical in form, but embodiments can include
circumferential ablational surfaces arranged on surfaces that
depart from strict cylindrical, and become more ovalular or
spherical, as shown in FIGS. 58A and 58B, with one or both of the
(proximal or distal) ends being tapered. By way of further
description of the ablational surface, it includes ablational
delivery elements such as non-penetrating radiofrequency
electrodes, but other types of ablational energy elements are
includes as embodiments as well, and as described further below.
Exemplary arrangements of radiofrequency electrodes are shown in
FIGS. 5, and 7-9. Arrangements of energy delivery elements that
create a fractional or partial ablation within a target area, as
well as the ablation patterns they deliver to target tissue, are
described further below, and depicted in FIGS. 48-55. Another
feature shared by energy delivery element patterns provided herein
is that although the ablation pattern is on a surface that may be
pressed into therapeutic contact by an expandable member, the
immediate surface upon which the energy delivery elements are
arranged is substantially non-distensible, thus the density of
elements across the surface remains constant.
[0098] Additional and alternative device embodiments are included
as described below, and depicted in FIGS. 9-23, 26-47, and 56.
These device embodiments provide an ablational surface of less than
a fully circumferential span. In terms of the circumference with
respect to the device itself, some embodiments provide an
ablational surface of about 90 degrees, some embodiments provide an
ablational surface of about 180 degrees, however embodiments
include any partially-circumferential span. Ablational energy
elements include radiofrequency electrodes, among others, and may
be arranged on the surface in any pattern, including
fractionally-ablating patterns. The arc of a curved treatment area
can be anything less than 360 degrees, however it is typically less
than 180 degrees, and more particularly may include a smaller
radial expanse such as arcs of about 5 degrees, about 10 degrees,
about 15 degrees, about 30 degrees, about 45 degrees, about 60
degrees, and about 90 degrees.
[0099] Turning now to an aspect of therapeutic ablation methods
provided herein, that of determining an appropriate site for
ablational treatment (FIG. 3), as well as the amount of ablational
energy to be applied during such treatment, such determinations
follow from the total amount of clinical information that a
clinician can gather on a particular patient.
[0100] In some embodiments, a preliminary endoscopic or direct
visual examination of the features of a lesion to be treated may be
appropriate so that any patient-specific features may be mapped
out, as well as an evaluation of the general dimensions of the
patient's alimentary canal, particularly with regard to the
specific anatomical location of the lesion. Such information may be
obtained by direct visual observation or through an instrument such
as an endoscope or colonscope. Still further, identification and/or
localization of the lesion(s) may be accomplished by other
diagnostic methods, including non-invasive penetrative imaging
approaches such as narrow band imaging from an endoscope. In one
aspect, evaluation of a site includes identifying the locale of the
site, including size, orientation and dimensions of one or more
lesions. In another aspect, evaluation of target tissue includes
identifying a multiplicity of sites, if there is more than one
site, and further identifying their locale and their respective
dimensions. In still another aspect, evaluating target sites may
include identifying or grading any pathology or injury to a
specific site, particularly identifying any areas of clinical
significance or concern that are overlapping or near the areas to
be targeted for ablation.
[0101] Once target sites for ablation have been identified, target
tissue containing the lesion may be treated with embodiments of an
inventive ablational device and associated methods as described
herein. Evaluation of the status of target tissue sites for
ablation, particularly by visualization approaches, may also be
advantageously implemented as part of an ablational therapy method
(FIG. 3), as for example, in close concert with the ablation,
either immediately before the application of ablational energy
(such as radiant energy), and/or immediately thereafter. Further,
the treatment site can be evaluated by any diagnostic or visual
method at some clinically appropriate time after the ablation
treatment, as for example a few days, several weeks, or several few
months, or at anytime when clinically indicated following
ablational therapy. In the event that any follow-up evaluation
shows either that the therapy was unsatisfactorily complete, or
that there is a recovery in the population of cells targeted for
ablation, a repetition of the ablational therapy may be
indicated.
[0102] Turning now to aspects of ablational devices that can be
directed toward ablation based treatment of lesions, as described
in detail herein, ablational devices have an ablational structure
arrayed with energy-transmitting elements such as electrodes. In
some embodiments, depending on the type of ablatative energy being
used in the therapy, the devices may be mounted on, or supported by
any appropriate instrument that allows movement of the ablational
surface to the local of a target site. Such instruments are adapted
in form and dimension to be appropriate for reaching the target
tissue site, and may include simple catheters adapted for the
purpose; some embodiments of the insertive instrument include
endoscopes that, in addition to their supportive role, also provide
a visualization capability. In some embodiments of the method, an
endoscope separate from the supportive instrument may participate
in the ablational procedure by providing visual information.
[0103] Exemplary embodiments of the inventive device as described
herein typically make use of electrodes to transmit radiofrequency
energy, but this form of energy transmission is non-limiting, as
other forms of energy, and other forms of energy-transmission
hardware are included as embodiments of the invention. Ablational
energy, as provided by embodiments of the invention, may include,
by way of example, microwave energy emanating from an antenna,
light energy emanating from photonic elements, thermal energy
transmitted conductively from heated ablational structure surfaces
or as conveyed directly to tissue by heated gas or liquid, or a
heat-sink draw of energy, as provided by cryonic or cryogenic
cooling of ablational structure surfaces, or as applied by direct
contact of cold gas or fluid with tissue, or by heat-draw through a
wall of a device that separates the cold gas or fluid from the
tissue.
[0104] Embodiments of the ablational device include variations with
regard to the circumferential expanse of the ablational surface to
be treated, some embodiments provide a fully circumferential
ablation surface and others provide a surface that is less than
fully circumferential, as described above. Choosing the appropriate
device is a step included within the therapeutic method provided,
as shown in FIG. 3. These and other variation may provide
particular advantages depending on the nature, extent, locale, and
dimensions of the one or more targeted tissue sites on the wall the
alimentary canal. One embodiment of the invention includes a device
with an ablational surface that is fully circumferential, i.e.,
encompassing a radius of 360 degrees, such that a full radial zone
within a luminal organ is subject to ablation. Within that zone,
ablation may be implemented to a varying degree, depending on the
energy output and the pattern of the ablational elements (such as
electrodes), but with substantial uniformity within the zone of
ablation. This embodiment may be particularly appropriate for
treating widespread or diffuse lesion sites. In another embodiment
of the device, the ablational surface of the inventive device is
partially circumferential, such that it engages a fraction of the
full internal perimeter or circumference of a luminal organ. The
fractional portion of the circumference ablated on the inner
surface of a luminal organ depends on the size of the luminal organ
being treated (radius, diameter, or circumference) and on the
dimensions of the ablational surface, as detailed further below.
With regard to treating target lesion sites that are small and
discrete, the smaller or more discrete ablational surface provided
by this latter embodiment may be advantageous. In some embodiments,
the size of the ablation device corresponds to the size of the
lesion or lesion site to be treated. In one aspect, the ablation
device is selected to correspond to a size that is the same as the
target lesion. In another aspect, the ablation device is selected
to correspond to a size that is larger than the size of the target
lesion.
[0105] This type of operational control of a circumferential subset
of ablation energy elements around a 360-degree circumferential
array is analogous to the fractional operation of a patterned
subset of an electrode array, as described below in the section
titled "Electrode patterns and control of ablation patterns across
the surface area of tissue". In the partially-circumferential
operation of an array, a particular arc of the array is activated
to deliver energy to an arc of the circumference. In the
fractional-pattern operation of an array, energy is delivery to a
portion of the tissue in the target area, while another portion
receives insufficient energy to achieve ablation. In some
embodiments, these operational variations can be combined, that is,
a patterned subset of a circumferential arc can be activated.
[0106] FIGS. 3 and 4 together provide flow diagram depictions of
embodiments of the method for ablating tissue including a targeted
lesion. The diagrams represent common aspects of the embodiments of
the method, as delivered by two embodiments of the device, one
which has a 360 degree circumferential ablation structure, and one
which has an ablation structure comprising an arc of less than 360
degrees.
[0107] FIG. 3 is a flow diagram depicting an overview of the method
with a focus on patient evaluation and determination of a
clinically appropriate site within the alimentary canal for
ablational treatment of a targeted lesion. In another step, a
responsible clinician makes an informed choice with regard to the
appropriate embodiment with which to treat the patient, i.e.,
either a device with the 360 degree electrode array 100A, or a
device 100B with the electrodes arrayed in an arc of less than 360
degrees. In the event that the device 100A is chosen for use,
another treatment choice may be made between operating the
electrodes throughout the 360 degree circumference, or whether to
operate a radial subset of the electrode array. In another step, a
clinician further considers and makes a determination as to the
protocol for ablation, considering the amount of energy to be
delivered, the energy density, the duration of time over which
energy is to be delivered. These considerations take into the
account the surface area to be ablated, the depth of tissue which
is to be treated, and the features of the electrode array, whether,
for example, it is to be a fractional electrode, and which pattern
may be desirable. Regardless of the device chosen, another
preliminary step to operating the method may include a closer
evaluation of the target tissue site(s) within the alimentary
canal. Evaluation of the site may include the performance of any
visualization or diagnostic method that provides a detailed census
of the number of discrete target tissue sites, their dimensions,
their precise locations, and/or their clinical status, whether
apparently normal or abnormal. This step is shown following the
choice of instrument, but may occur simply in conjunction with
diagnosis, or at any point after diagnosis and general localization
of the target tissue. In any case, an evaluating step is typically
performed prior to ablation, as outlined in the operational steps
of the method, as shown in the flow diagram of FIG. 4.
[0108] FIG. 4 is a flow diagram depicting an exemplary method of
ablating a lesion once localized and a choice has been made
regarding the preferred ablational device. The method includes an
evaluation of the site, including lesion particulars such as
location, stage, determination of the number of lesion sites, and
the dimensions, as described above, and using approaches detailed
in the references provided in the background, and/or by using
whatever further approaches may be known by those practiced in the
art. The method continues with insertion of the instrument and the
movement of the ablational structure to the locale of the target
tissue to be ablated. Subsequently, more refined movements of the
ablational structure may be performed that create a therapeutically
effective contact between the ablational structure and the target
tissue site. In the event that the 360 degree embodiment of the
device 100A is chosen, therapeutically effective contact may be
made by inflating a balloon underlying the electrode array. In the
event that the embodiment chosen is 100B, the device with an
electrode surface spanning an arc of less than 360 degrees,
movements that bring the ablational surface into therapeutically
effective contact may include any of inflation of a balloon,
inflation of a deflection member, and/or movement of a deflection
member, all of which are described further below. The instrument or
other device may also be used to deflect tissue in order to expose
a target site containing a lesion.
[0109] After therapeutically-effective contact is made, by either
device embodiment 100A or 100B, and by whatever type of movement
was that was taken, a subsequent step includes the emission of
ablational energy from the device. Variations of ablational energy
emission may include ablating a single site as well as moving the
instrument to a second or to subsequent sites that were identified
during the evaluation step. Following the ablational event, a
subsequent step may include an evaluation of the treated target
site; alternatively evaluation of the consequences of ablation may
include the gathering of clinical data and observation of the
patient. In the event that an endoscope is included in the
procedure, either as the instrument supporting the ablational
structure, or as a separate instrument, such evaluation may occur
immediately or very soon after ablation, during the procedure, when
instruments are already in place. In other embodiments of the
method, the treated site may be evaluated at any clinically
appropriate time after the procedure, as for example the following
day, or the following week, or many months thereafter. In the event
that any of these evaluations show an ablation that was only
partially complete, or show an undesired repopulation of targeted
cells, the method appropriately includes a repetition of the steps
just described and schematically depicted in FIG. 4.
[0110] In addition to observation by direct visual approaches, or
other diagnostic approaches of site of ablation per se, evaluation
of the consequences of ablation may include the gathering of a
complete spectrum of clinical and metabolic data from the patient.
Such information includes any test that delivers information
relevant to the metabolic status of the patient such as the
information gathered when determining the appropriateness of
ablational intervention, as was made in the first step of FIG.
3.
Device and Method for 360 Degree Circumferential Ablation
[0111] Methods for accomplishing ablation of targeted cells of a
lesion according to this invention include the emission of radiant
energy at conventional levels to accomplish ablation of the
targeted lesion. In one embodiment, as shown in FIGS. 1A, 1C, and
2A, an elongated flexible shaft 41 is provided for insertion into
the body in any of various ways selected by a medical care
provider. The shaft may be placed endoscopically, e.g. passing
through the mouth further into the proximal esophagus or other
lesion site in the esophagus or the stomach. Alternatively, it may
be placed surgically, or by any other suitable approach such as
through or into the anus or rectum, as needed to access the lesion
site.
[0112] In this embodiment, radiant energy distribution elements or
electrodes on an ablation structure 101 are provided at a distal
end of the flexible shaft 41 to provide appropriate energy for
ablation as desired. In typical embodiments described in this
section, the radiant energy distribution elements are configured
circumferentially around 360 degrees. Alternatively to using
emission of RF energy from the ablation structure, alternative
energy sources can be used with the ablation structure to achieve
tissue ablation and may not require electrodes. Such energy sources
include: ultraviolet light, microwave energy, ultrasound energy,
thermal energy transmitted from a heated fluid medium, thermal
energy transmitted from heated element(s), heated gas such as steam
heating the ablation structure or directly heating the tissue
through steam-tissue contact, light energy either collimated or
non-collimated, cryogenic energy transmitted by cooled fluid or gas
in or about the ablation structure or directly cooling the tissue
through cryogenic fluid/gas-tissue contact. Embodiments of the
system and method that make use of these aforementioned forms of
ablational energy include modifications such that structures,
control systems, power supply systems, and all other ancillary
supportive systems and methods are appropriate for the type of
ablational energy being delivered.
[0113] In some embodiments of a fully circumferential ablation
device, the flexible shaft comprises a cable surrounded by an
electrical insulation layer and comprises a radiant energy
distribution elements located at its distal end. In one form of the
invention, a positioning and distending device around the distal
end of the instrument is of sufficient size to contact and expand
the walls of the gastrointestinal tract lumen or organ in which it
is placed both in the front of the energy distribution elements as
well as on the sides of the energy distribution elements. For
example, the distal head of the instrument can be supported at a
controlled distance from the wall of the gastrointestinal tract
lumen or organ by an expandable balloon or inflation member, such
that a therapeutically-effective contact is made between the
ablation structure and the target site so as to allow regulation
and control the amount of energy transferred to the target tissue
within the lumen when energy is applied through the electrodes. The
balloon is preferably bonded to a portion of the flexible shaft at
a point spaced from the distal head elements.
[0114] Some embodiments of a fully-circumferential ablation device
include a distendible or expandable balloon member as the vehicle
to deliver the ablation energy. One feature of this embodiment
includes means by which the energy is transferred from the distal
head portion of the invention to the membrane comprising the
balloon member. For example, one type of energy distribution that
may be appropriate and is incorporated herein in its entirety is
shown in U.S. Pat. No. 5,713,942, in which an expandable balloon is
connected to a power source that provides radio frequency power
having the desired characteristics to selectively heat the target
tissue to a desired temperature. A balloon per embodiments of the
current invention may be constructed of an electroconductive
elastomer such as a mixture of polymer, elastomer, and
electroconductive particles, or it may comprise a nonextensible
bladder having a shape and a size in its fully expanded form which
will extend in an appropriate way to the tissue to be contacted. In
another embodiment, an electroconductive member may be formed from
an electroconductive elastomer wherein an electroconductive
material such as copper is deposited onto a surface and an
electrode pattern is etched into the material and then the
electroconductive member is attached to the outer surface of the
balloon member. In one embodiment, the electroconductive member,
e.g. the balloon member 105, has a configuration expandable in the
shape to conform to the dimensions of the expanded (not collapsed)
inner lumen of the human lower gastrointestinal tract.
[0115] In addition, such electroconductive member may consist of a
plurality of electrode segments arrayed on an ablation structure
101 having one or more thermistor elements associated with each
electrode segment by which the temperature from each of a plurality
of segments is monitored and controlled by feedback arrangement. In
another embodiment, it is possible that the electroconductive
member may have means for permitting transmission of microwave
energy to the ablation site. In yet another embodiment, the
distending or expandable balloon member may have means for carrying
or transmitting a heatable fluid within one or more portions of the
member so that the thermal energy of the heatable fluid may be used
as the ablation energy source.
[0116] Some embodiments of a fully circumferential ablation device
include a steerable and directional control means, a means for
accurately sensing depth of cautery, and appropriate alternate
embodiments so that in the event of a desire not to place the
electroconductive elements within the membrane forming the
expandable balloon member it is still possible to utilize the
balloon member for placement and location control while maintaining
the energy discharge means at a location within the volume of the
expanded balloon member, such as at a distal energy distribution
head.
[0117] One approach a practitioner may use to determine the
appropriate diameter ablation catheter to use with a particular
patient is to use in a first step a highly compliant balloon
connected to a pressure sensing mechanism. The balloon may be
inserted into a luminal organ containing the target lesion and
positioned at the desired site of the ablation and inflated until
an appropriate pressure reading is obtained. The diameter of the
inflated balloon may be determined and an ablation device of the
invention having a balloon member capable of expanding to that
diameter chosen for use in the treatment. In one aspect of the
method of this invention, it is desirable to expand the expandable
electroconductive member such as a balloon sufficiently to occlude
the vasculature of the submucosa, including the arterial, capillary
or venular vessels. The pressure to be exerted to do so should
therefore be greater than the pressure exerted by such vessels.
[0118] In other embodiments of the method, electronic means are
used for measuring the luminal target area of the target lesion
site so that energy may be appropriately normalized for the surface
area of the target tissue. These aspects of the method are
described in detail in U.S. patent application Ser. No. 12/143,404,
of Wallace et al., entitled "Electrical means to normalize
ablational energy transmission to a luminal tissue surface of
varying size", as filed on Jun. 20, 2008, which is incorporated in
entirety. An embodiment of a device with a 360 degree ablational
surface is described in detail in that application, and is depicted
in FIGS. 57A-57D of this application. Pressure sensing means may
also be used to measure the size of a lumen in preparation for an
ablation treatment, as described in U.S. patent application Ser.
No. 11/244,385 of Jackson, published as US 2006/0095032.
[0119] An embodiment of a device disclosed in U.S. patent
application Ser. No. 12/143,404, of Wallace et al will be described
here briefly, in order to provide an embodiment that includes a
360-degree ablational surface arranged on an overlapping support
that expands in accordance with a balloon enclosed within the
circumference of the support. Although the circumference of the
device as a whole expands with the balloon, the ablational surface
itself is non-distensible, and maintains its electrode density.
FIGS. 57A-57D provide perspective views of an ablation device 100
with an overlapping electrode support 360 furled around an
expandable balloon 105. An array of ablational energy delivery
elements 101 such as radiofrequency electrodes is arranged on the
exterior surface of the electrode support. The operative element is
mounted on the distal end of an ablation catheter, of which the
distal portion of a shaft 41 is seen, and around which the balloon
105 is configured. FIG. 57A shows the electrode support 360 pulled
away from the balloon 105 to clarify that a portion of the support
and an inner edge 362 is adherent to the balloon, and another
portion and its outer edge 364 is not connected to the balloon.
FIG. 57B shows the non-adherent portion of the electrode support
360 furled around the balloon 105 in a deployable configuration,
the non-adherent portion and its edge overlapping around the
adherent portion. FIG. 57C shows an optional feature of the device
100A, one or more elastic bands 380 wrapped around the electrode
support 360. In some embodiments, the elastic band 380 material is
a conductive elastomer, as described in greater detail below, which
can be included in a size-sensing circuit to provide information
related to the degree of expansion of the operative element. FIG.
57D shows the device of FIG. 57C in a collapsed state, with balloon
portion 105 being uninflated (or deflated), this being the state of
the device when it is being deployed into a lumen and being
positioned at a target site, as well as the state of the device
after delivering ablation energy and about to be removed from the
lumen.
[0120] Another embodiment of an ablation device with a fully
circumferential ablation surface is provided in FIGS. 58A-58B. This
particular device embodiment 400 is adapted to present an
ablational surface 101 into a concave or inwardly tapered target
site such as distal portion of the antrum of the stomach, or in the
vicinity of the pylorus. The device includes an ablational surface
circumferentially arranged on the distal portion of an expandable
member 105, the expandable member mounted around the distal end 110
of the shaft of an endoscope 111. FIG. 58A shows the device in a
deployed configuration. FIG. 58B shows the device with the
expandable member in an unexpanded or collapsed state, as would be
appropriate for deployment of the device to a target tapered
surface, or as would be appropriate for removal from the ablational
site. FIG. 58C shows the device of FIG. 58A as it can be deployed
into a tapered or concave target site such as the pylorus 9 or
other portions of the stomach. FIG. 58D shows the device of FIG.
58A in an alternative configuration, with the electrode bearing
surface of the device reversed such that it is facing proximally,
and can thus be pulled retrograde into a tapered or concave
site.
Electrode Patterns and Control of Ablation Patterns Across the
Surface Area of Tissue
[0121] Some aspects of embodiments of the ablational device and
methods of use will now be described with particular attention to
the electrode patterns present on the ablation structure. The
device used is shown schematically in FIGS. 5-7. As shown in FIG.
6, the elongated flexible shaft 41 of a device with a fully
circumferential ablation surface is connected to a multi-pin
electrical connector 94 which is connected to the power source and
includes a male luer connector 96 for attachment to a fluid source
useful in expanding the expandable member. The elongated flexible
shaft has an electrode 98 wrapped around the circumference. The
expandable member of the device shown in FIGS. 5 and 6 further
includes three different electrode patterns, the patterns of which
are represented in greater detail in FIGS. 7A-7C. Typically, only
one electrode pattern is used in a device of this invention,
although more than one may be included. In the device shown in FIG.
5, the elongated flexible shaft 41 comprises six bipolar rings 62
with about 2 mm separation at one end of the shaft (one electrode
pattern), adjacent to the bipolar rings is a section of six
monopolar bands or rectangles 65 with about 1 mm separation (a
second electrode pattern), and another pattern of bipolar axial
interlaced finger electrodes 68 is positioned at the other end of
the shaft (a third electrode pattern). In this device, a null space
70 is positioned between the last of the monopolar bands and the
bipolar axial electrodes. The catheter used in the study was
prepared using a polyimide flat sheet of about 1 mil (0.001'')
thickness coated with copper. The desired electrode patterns were
then etched into the copper.
[0122] Alternative electrode patterns are shown in FIGS. 8A-8D as
80, 84, 88, and 92, respectively. Pattern 80 is a pattern of
bipolar axial interlaced finger electrodes with about 0.3 mm
separation. Pattern 84 includes monopolar bands with 0.3 mm
separation. Pattern 88 is that of electrodes in a pattern of
undulating electrodes with about 0.25 mm separation. Pattern 92
includes bipolar rings with about 0.3 mm separation. In this case
the electrodes are attached to the outside surface of a balloon 72
having a diameter of about 18 mm. The device may be adapted to use
radio frequency by attaching wires 74 as shown in FIG. 5 to the
electrodes to connect them to the power source.
[0123] The preceding electrode array configurations are described
in the context of an ablation structure with a full 360 degree
ablation surface, but such patterns or variants thereof may also be
adapted for ablation structures that provide energy delivery across
a lesion target surface that is less than completely
circumferential, in structures, for example, that ablate over any
portion of a circumference that is less than 360 degrees, or for
example structures that ablate around a radius of about 90 degrees,
or about 180 degrees.
[0124] Embodiments of the ablation system provided herein are
generally characterized as having an electrode pattern that is
substantially flat on the surface of an ablation support structure
and which is non-penetrating of the tissue that it ablates. The
electrode pattern forms a contiguous treatment area that comprises
some substantial radial aspect of a luminal organ; this area is
distinguished from ablational patterns left by electrical
filaments, filament sprays, or single wires. In some embodiments of
the invention the radial portion may be fully circumferential; the
radial portion of a luminal organ that is ablated by embodiments of
the invention is function of the combination of (1) the
circumference of the organ, (2) the dimensions of the electrode
pattern and (3) the size and orientation of the target lesion site.
Thus, at the high end, as noted, the radial expanse of a treatment
area may be as large as 360 degrees, and as small as about 5 to 10
degrees, as could be the case in a treatment area within the
stomach, the proximal esophagus, colon or anus
[0125] Embodiments of the ablational energy delivery system and
method provided are also characterized by being non-penetrating of
the target tissue. Ablational radiofrequency energy is delivered
from the flat electrode pattern as it makes therapeutic contact
with the tissue surface of a treatment area, as described elsewhere
in this application; and from this point of surface contact, energy
is directly inwardly to underlying tissue layers.
[0126] Some embodiments of the ablational system and method
provided herein can be further characterized by the electrode
pattern being configured to achieve a partial or fractional
ablations, such that only a portion of the tissue surface receives
sufficient radiofrequency energy to achieve ablation and another
portion of the surfaces receives insufficient energy to achieve
ablation. The system and method can be further configured to
control the delivery of radiofrequency energy inwardly from the
tissue surface such that depth of tissue layers to which energy
sufficient for ablation is delivered is controlled.
[0127] Controlling the fraction of the tissue surface target area
that is ablated, per embodiments of the invention, is provided by
various exemplary approaches: for example, by (1) the physical
configuration of electrode pattern spacing in a comparatively
non-dense electrode pattern, and by (2) the fractional operation of
a comparatively dense electrode array, in a billboard-like manner.
Generally, creating a fractional ablation by physical configuration
of the electrode pattern includes configuring the electrode pattern
such that some of the spacing between electrodes is sufficiently
close that the conveyance of a given level of energy between the
electrodes sufficient to ablate tissue is allowed, and other
spacing between electrodes is not sufficiently close enough to
allow conveyance of the level of energy sufficient to ablate.
Embodiments of exemplary electrode patterns that illustrate this
approach to creating fractional ablation are described below, and
depicted in FIGS. 48-55. The creation of an ablation pattern by
activating a subset of electrodes represents an operation of the
inventive system and method which is similar to the described
above, wherein an ablational structure with a fully circumferential
pattern of electrodes can be operated in a manner such that only a
radial fraction of the electrodes are operated.
[0128] The ablation system of the invention includes an electrode
pattern with a plurality of electrodes and a longitudinal support
member supporting the electrode pattern, as described in numerous
embodiments herein. Energy is delivered to the electrodes from a
generator, and the operation of the generator is controlled by a
computer-controller in communication with the generator, the
computer controller controlling the operating parameters of the
electrodes. The computer controller has the capability of directing
the generator to deliver energy to all the electrodes or to a
subset of the electrodes. The controller further has the ability to
control the timing of energy delivery such that electrodes may be
activated simultaneously, or in subsets, non-simultaneously.
Further, as described elsewhere, the electrodes may be operated in
a monopolar mode, in a bipolar mode, or in a multiplexing mode.
These various operating approaches, particularly by way of
activating subsets of electrodes within patterns, allow the
formation of patterns that, when the pattern is in therapeutic
contact with a target surface, can ablate a portion of tissue in
the target area, and leave a portion of the tissue in the target
area non-ablated.
[0129] Generally, creating a fractional ablation by an operational
approach with a comparatively dense electrode array includes
operating the electrode pattern such that the energy delivered
between some of the electrodes is sufficient to ablate, whereas
energy sufficient to ablate is not delivered between some of the
electrodes. Embodiments of exemplary electrode patterns that
illustrate this approach to creating fractional ablation are
described below, and depicted in FIGS. 48-55.
[0130] Another aspect of controlling the fraction of tissue
ablation, as well as controlled ablation generally relates to
controlling the depth of ablation into lesion tissue layers within
the target area. Energy is delivered inwardly from the surface,
thus with modulated increases in energy delivery, the level of
ablation can be controlled such that, for example, the ablated
tissue may consist only of tissue in the epithelial layer.
Additionally or alternatively, it may consist of tissue in the
epithelial layer and the lamina propria layers, or it may consist
of tissue in the epithelial, lamina propria and muscularis mucosal
layers, or it may consist of tissue in the epithelial, lamina
propria, muscularis mucosa, and submucosal layers, or it may
consist of tissue in the epithelial layer, the lamina propria, the
muscularis mucosae, the submucosa, and the muscularis propria
layers. Alternatively, the depth of ablation into the layers of the
targeted lesion or site may be controlled to ablate to a desired
tissue layer.
[0131] Embodiments of the invention include RF electrode array
patterns that ablate a fraction of tissue within a given single
ablational area, exemplary fractional arrays are shown in FIGS.
48A, 49A, and 50A. These fractional ablation electrode arrays may
be applied, as above, to above to ablational structures that
address a fully circumferential target area, or a structure that
addresses any portion of a full circumference such as 90 degree
radial surface, or a 180 degree radial surface. FIG. 48A shows a
pattern 180 of linear electrodes 60 aligned in parallel as stripes
on a support surface. The electrodes are spaced apart sufficiently
such that when pressed against tissue in therapeutic contact, the
burn left by distribution of energy through the electrodes results
in a striped pattern 190 on the target tissue as seen in FIG. 48B
corresponding to the electrode pattern, with there being stripes of
burned or ablated tissue 3a that alternate with stripes of
unburned, or substantially unaffected tissue 3b. In some
embodiments of the method, particularly in ablation structures that
address a target area of less than 360 radial degrees, such as a
target surface that is about 180 degrees, or more particularly
about 90 degrees of the inner circumference of a lumen, the
ablation may be repeated with the ablational structure positioned
at a different angle. FIG. 48C, for example, depicts a tissue burn
pattern 191 created by a first ablational event followed by a
second ablational event after the ablational structure is laterally
rotated by about 90 degrees. FIG. 48D, for another example, depicts
a tissue burn pattern 192 created by a first ablational event
followed by a second ablational event after the ablational
structure is laterally rotated by about 45 degrees.
[0132] The effect of an ability to ablate a tissue surface in this
manner adds another level of fine control over tissue ablation,
beyond such parameters as total energy distributed, and depth of
tissue ablation. The level of control provided by fractional
ablation, and especially when coupled with repeat ablational events
as described above in FIGS. 48C and 48D, is to modulate the surface
area-distributed fraction of tissue that is ablated to whatever
degree the local maximal ablation level may be. The fractional
ablation provided by such fractional electrode pattern may be
particularly advantageous when the effects of ablation are not
intended to be absolute or complete, but instead a functional
compromise of tissue, or of cells within the tissue is desired. In
some therapeutic examples, thus, a desirable result could be a
partial reduction in overall function of a target area, rather than
a total loss of overall function.
[0133] FIGS. 49A and 50A depict other examples of a
fractionally-ablating electrode pattern on an ablation structure,
and FIGS. 49B and 50B show the respective fractional burn patterns
on tissue that have been treated with these electrode patterns. In
FIG. 49A a pattern of concentric circles 182 is formed by wire
electrodes that (from the center and moving outward) form a +--++-
pattern. When activated, the tissue between +- electrodes is
burned, and the tissue between ++ electrode pairs or -- electrode
pairs is not burned. Thus, the concentric pattern 192 of FIG. 49B
is formed. Embodiments of fractionally-ablating electrode patterns
such as those in FIG. 49A need not include perfect circles, and the
circles (imperfect circles or ovals) need not be perfectly
concentric around a common center.
[0134] Similarly, FIG. 50A shows a checkerboard pattern 184 of +
and - electrodes which when activated create a burn pattern 194 as
seen in FIG. 50B. Tissue that lies between adjacent + and -
electrodes is burned, while tissue that lies between adjacent ++
electrodes or -- electrode pairs remains unburned. FIG. 50B
includes a representation of the location of the + and - electrodes
from the ablation structure in order to clarify the relative
positions of areas that are burned 3a and the areas that remain
substantially unburned 3b.
[0135] Embodiments of the invention include RF electrode array
patterns that ablate a fraction of tissue within a given single
ablational area by virtue of operational approaches, whereby some
electrodes of a pattern are activated, and some are not, during an
ablational event visited upon a target area. Exemplary fractional
arrays are shown in FIGS. 51A, 52A, 53A and 54A. These fractional
ablation electrode arrays may be applied, as above, to ablational
structures that address a fully circumferential target area, or a
structure that addresses any portion of a full circumference such
as, by way of example, a 90 degree radial surface, or a 180 degree
radial surface.
[0136] FIG. 51A shows a checkerboard electrode pattern during an
ablational event during which all electrode squares of the
operational pattern 186A are operating, as depicted by the sparkle
lines surrounding each electrode. Operating the electrode pattern
186A in this manner produces an ablation pattern 196A, as seen in
FIG. 51B, wherein the entire surface of tissue within the treatment
area is ablated tissue 3a. FIG. 52A, on the other hand, shows a
checkerboard electrode pattern during an ablational event during
which only every-other electrode square of the operational pattern
186B is operating, as depicted by the sparkle lines surrounding
each activated electrode. Operating the electrode pattern 186B in
this manner produces an ablation pattern 196B, as seen in FIG. 52B,
wherein a checkerboard fractionally ablated pattern with a
dispersed pattern of ablated squares 3a of tissue 3a alternate with
square areas of tissue 3b that are not ablated.
[0137] FIG. 53A shows a striped linear electrode pattern of
alternating + and - electrodes during an ablational event during
which all electrode squares of the operational pattern 188A are
operating, as depicted by the sparkle lines surrounding each linear
electrode. Operating the electrode pattern in this manner 188A
produces an ablation pattern 198A, as seen in FIG. 53B, wherein the
entire surface of tissue within the treatment area is ablated
tissue 3a.
[0138] FIG. 54A, on the other hand, shows a striped linear
electrode pattern 188B of alternating + and - electrodes during an
ablational event during which alternate pairs of the linear
electrode pairs are operating, as depicted by the sparkle lines
surrounding the activated linear electrodes. Operating the
electrode pattern in this manner 188B produces an ablation pattern
198B, as seen in FIG. 54B, wherein stripes of ablated tissue 3a
within the treatment area alternate stripes of non-ablated tissue
3b.
[0139] FIG. 55 is a schematic rendering of a three dimensional view
of a target lesion region after it has been ablationally treated,
per embodiments of the invention. Ablated regions 3a are rendered
as regions distributed through the target area within a larger sea
of non-ablated tissue 3b. These regions are depicted as being
slightly conical in this schematic view, but in practice the
ablated tissue region may be more cylindrical in shape. The regions
3a are of approximately the same depth, because of the control
exerted over the depth of the ablation area into tissue layers, as
described herein. With such control, the regions 3a can vary with
respect of the layer to which they extend continuously from the
upper surface where ablational energy has been applied. The conical
regions are of approximately the same width or diameter, and
distributed evenly throughout the tissue, because of the control
over ablational surface area, as described herein. In this
particular example, the therapeutic target is actually a particular
type of cell 4b (open irregular spheres), for example, a nerve
cell, or endocrine secretory cell; and these cells are distributed
throughout the target area. The post-ablation therapeutic target
cells 4a (dark irregular spheres) are those which happened to be
included within the conical regions 3a that were ablated. The
post-ablation cells 4a may be rendered dysfunctional to varying
degree, they may be completely dysfunctional, they may be, merely
by way of illustrative example, on the average, 50% functional by
some measure, and there functionality may vary over a particular
range. It should be particularly appreciated however, per
embodiments of the invention, that the cells 4b, those not included
in the ablated tissue cones, are fully functional.
Controlling the Ablation in Terms of the Tissue Depth of the
Ablation Effect
[0140] In addition to controlling the surface area distribution of
ablation, as may be accomplished by the use of fractional ablation
electrodes as described above, or as controlled by the surface area
of electrode dimensions, ablation can be controlled with regard to
the depth of the ablation below the level of the tissue surface
where the ablative structure makes therapeutic contact with the
tissue. The energy delivery parameters appropriate for delivering
ablation that is controlled with regard to depth in tissue may be
determined experimentally.
[0141] FIG. 25 provides a schematic representation of the histology
of a target lesion wall as it is generally found within the
alimentary canal. The relative presence and depth and composition
of the layers depicted in FIG. 25 vary depending on anatomical
position, but the basic organization is similar. The layers of the
target site wall will be described in their order as seen FIG. 25
from top to bottom and in terms of the direction from which an
ablation structure would approach the tissue. The innermost layer
can be referred to as the surface (epithelium), and succeeding
layers can be understood as being below or beneath the "upper"
layers. The innermost layer of a target site within the
gastrointestinal tract is in direct contact with the nutrients and
processed nutrients as they move through the gut is a layer of
epithelium 12. This layer secretes mucous which protects the lumen
from abrasion and against the corrosive effect of an acidic
environment. Beneath the epithelium is a layer known as the lamina
propria 13, and beneath that, a layer known as the muscularis
mucosae 14. The epithelium 12, the lamina propria 13, and the
muscularis mucosae 14 collectively constitute the mucosa 15.
[0142] Below the mucosal layer 15 is a layer known as the submucosa
16, which forms a discrete boundary between the muscosal layer 15
above, and the muscularis propria 17 below. The muscularis propria
17 if present includes various distinct layers of smooth muscle
that enwrap the organ, in various orientations, including oblique,
circular, and the longitudinal layers. Enwrapping the muscularis
propria 17 is the serosa 18, which marks the outer boundary of the
organ.
[0143] As provided by embodiments of the invention, the ablation
applied to lesion tissue may be depth-controlled, such that only
the epithelium 12, or only a portion of the mucosal layer is
ablated, leaving the deeper layers substantially unaffected. In
other embodiments, the ablated tissue may commence at the
epithelium yet extend deeper into the submucosa and possibly the
muscularis propria, as necessary to achieve the desired therapeutic
effect.
Device and Method for Partially-Circumferential Ablation
[0144] One embodiment of a method of ablating lesion tissue
includes the use of an ablation device with an ablation structure
supported by conventional endoscopes 111, as illustrated in FIG.
24. An example of one commercially available conventional endoscope
111 is the Olympus "gastrovideoscope" model number GIF-Q160. While
the specific construction of particular commercially available
endoscopes may vary, as shown in FIG. 24, most endoscopes include a
shaft 164 having a steerable distal end 110 and a hub or handle 162
which includes a visual channel 161 for connecting to a video
screen 160 and a port 166 providing access to an inner working
channel within the shaft 164. Dials, levers, or other mechanisms
(not shown) will usually be provided on the handle 162 to allow an
operator to selectively steer the distal end 110 of the endoscope
111 as is well known in the endoscopic arts. In accordance with the
present invention, an ablation device, including an ablation
structure is advanced while supported at the distal end of an
endoscope. The ablation structure is deflectable toward a tissue
surface and the ablation structure is activated to ablate the
tissue surface. Within the gastrointestinal tract, variously sized
tissue surface sites can selectively be ablated using the device.
As will be further described, the ablational structure of
embodiments described in this section do not circumscribe a full
360 degrees, but rather circumscribe a fraction of 360 degrees, as
will be described further below.
[0145] In general, in one aspect a method of ablating lesion tissue
in the gastrointestinal tract is provided, more particularly
lesions such as benign, pre-cancerous and early cancerous lesions
that originate within the epithelium and are limited to the mucosal
layer of the gastrointestinal tract. The method includes advancing
an ablation structure into the gastrointestinal tract while
supporting the ablation structure with an endoscope. In some
embodiments, advancing the structure into the gastrointestinal
tract may be sufficient to place the ablational structure of the
device into close enough proximity in order to achieve therapeutic
contact. In other embodiments, a subsequent step may be undertaken
in order to achieve an appropriate level of therapeutic contact.
This optional step will be generally be understood as moving the
ablation structure toward the target lesion site. The method thus
may further include moving at least part of the ablation structure
with respect to the endoscope and toward a tissue surface; and
activating the ablation structure to ablate the tissue surface.
Moving at least part of the ablation structure with respect to the
endoscope can include movement toward, away from or along the
endoscope. Moving the ablational structure toward a target tissue
surface may be performed by structures in ways particular to the
structure. For example, the structure can be moved by inflating a
balloon member, expanding a deflection member, or moving a
deflection member. The function of such movement is to establish a
therapeutically effective contact between the ablational structure
and the target site. A therapeutically effective contact includes
the contact being substantial and uniform such that the highly
controlled electrical parameters of radiant emission from the
electrode result in similarly highly controlled tissue ablation.
Some embodiments of the invention further include structure and
method for locking or securing such a therapeutically effective
contact once established. Thus, some embodiments include a position
locking step that, for example, uses suction to secure the
connection between the ablation structure and the tissue site.
[0146] As shown in FIGS. 9, 10, 11, and 26, in one aspect a method
of ablating lesion tissue includes an ablation device 100 for
ablating a tissue surface 3, wherein the device 100 includes an
ablating structure, for example, an ablation structure 101
supported by an endoscope 111. The method includes ablating tissue
in a lesion region by the steps of (1) advancing the ablation
structure 101 into the lesion region; (2) deflecting the ablation
structure 101 toward a lesion tissue surface 3; and (3) activating
the ablation structure to ablate the lesion 3. As shown in FIG. 9,
the device 100 can additionally include a housing 107, electrical
connections 109, an inflation line 113 and an inflation member or
balloon 105.
[0147] The ablation structure 101, in one embodiment is an
electrode structure configured and arranged to deliver energy
comprising radiofrequency energy to the mucosal layer. It is
envisioned that such an ablation structure 101 can include a
plurality of electrodes. For example, two or more electrodes may be
part of an ablation structure. The energy may be delivered at
appropriate levels to accomplish ablation of mucosal or submucosal
level tissue, or alternatively to cause therapeutic injury to these
tissues, while substantially preserving muscularis tissue. The term
"ablation" as used herein generally refers to thermal damage to the
tissue causing any of loss of function that is characteristic of
the tissue, or tissue necrosis. Thermal damage can be achieved
through heating tissue or cooling tissue (i.e. freezing). In some
embodiments ablation is designed to be a partial ablation.
[0148] Although radiofrequency energy, as provided by embodiments
of the invention, is one particular form of energy for ablation,
other embodiments may utilize other energy forms including, for
example, microwave energy, or photonic or radiant sources such as
infrared or ultraviolet light, the latter possibly in combination
with improved sensitizing agents. Photonic sources can include
semiconductor emitters, lasers, and other such sources. Light
energy may be either collimated or non-collimated. Other
embodiments of this invention may utilize heatable fluids, or,
alternatively, a cooling medium, including such non-limiting
examples as liquid nitrogen, Freon.TM., non-CFC refrigerants,
CO.sub.2 or N.sub.2O as an ablation energy medium. For ablations
using hot or cold fluids or gases, the ablation system may include
an apparatus to circulate the heating/cool medium from outside the
patient to the heating/cooling balloon or other element and then
back outside the patient again. Mechanisms for circulating media in
cryosurgical probes are well known in the ablation arts. For
example, and incorporated by reference herein, suitable circulating
mechanisms are disclosed in U.S. Pat. No. 6,182,666 to Dobak; U.S.
Pat. No. 6,193,644 to Dobak; U.S. Pat. No. 6,237,355 to Li; and
U.S. Pat. No. 6,572,610 to Kovalcheck.
[0149] In a particular embodiment, the energy delivered to the
lesion in the gastrointestinal tract comprises radiofrequency
energy that can be delivered from the energy delivery device 100.
Radiofrequency energy can be delivered in a number of ways.
Typically, the radiofrequency energy will be delivered in a bipolar
fashion from a bipolar array of electrodes positioned on the
ablation structure 101, in some cases on an expandable structure,
such as a balloon, frame, cage, or the like, which can expand and
deploy the electrodes directly against or immediately adjacent to
the mucosal tissue so as to establish a controlled level of
therapeutic contact between the electrodes and the target tissue
(e.g., through direct contact or through a dielectric membrane or
other layer). Alternatively, the electrode structure may include a
monopolar electrode structure energized by a radiofrequency power
supply in combination with a return electrode typically positioned
on the patient's skin, for example, on the small of the back. In
any case, the radiofrequency energy is typically delivered at a
high energy flux over a very short period of time in order to
injure or ablate only the mucosal or submucosal levels of tissue
without substantially heating or otherwise damaging the muscularis
tissue. In embodiments where the ablation structure includes a
plurality of electrodes, one or more of the electrodes can be
bipolar or monopolar, and some embodiments include combinations of
bipolar and monopolar electrodes.
[0150] The ablation structure 101 can be arranged and configured in
any of a number ways with regard to shape and size in order to
treat the targeted lesion. Typically, the array has an area in the
range from about 0.5 cm.sup.2 to about 9.0 cm.sup.2. Typical shapes
would include rectangular, circular or oval. In one embodiment, the
ablation structure 101 has an area of about 2.5 cm.sup.2. In
another embodiment, the ablation structure 101 has an area of about
4 cm.sup.2 and dimensions of about 2 cm. by 2 cm.
[0151] The housing 107 of the ablation device 100 is arranged and
configured to support the ablation structure 101. The housing 107
can be made of any suitable material for withstanding the high
energy flux produced by the ablation structure 101. As shown in
FIGS. 9-14, 17, 18, 21, and 22, in one embodiment, the housing 107
is sandwiched between the ablation structure 101 and an endoscope
111 when the ablation device 100 is supported by an endoscope 111.
One end of the ablation structure 101 can be further away from the
endoscope than the other end to improve ease of contact with the
targeted tissue (not shown). For example, to ensure the proximal
end of the ablation structure 101 makes contact with the targeted
tissue, the proximal end of the electrode may be supported by a
tapered housing member 107.
[0152] The electrical connections 109 of the ablation device
connect the ablation structure 101 to a power source. The
electrical connections 109 can include a single wire or plurality
of wires as needed to provide controlled energy delivery through
the ablation structure 101. In one embodiment, the electrical
connections 109 include low electrical loss wires such as litz
wire.
[0153] The inflation line 113 is arranged and configured to
transport an expansion medium, typically a suitable fluid or gas,
to and from the inflation member. In one embodiment, the inflation
line is a flexible tube. The inflation line 113 can be made of
polymer or co-polymers, such as the non-limiting examples of
polyimide, polyurethane, polyethylene terephthalate (PET), or
polyamides (nylon). The inflation member 105 is designed to deflect
the ablation device 100 in relation to a target tissue surface 3.
The inflation member 105 can be reversibly expanded to an increased
profile.
[0154] In one embodiment, the inflation member 105 additionally
serves as an attachment site for support of the ablation device 100
by an endoscope 111. As shown in FIGS. 9-14, 17, 18, 21 and 22, the
inflation member 105 can be deployed from a low profile
configuration or arrangement (see FIGS. 10, and 20) to an increased
profile configuration or arrangement (see FIGS. 11-14, 17-19) using
the expansion medium. In preparation for ablation, when the
inflation member 105 is sufficiently inflated, deflection of the
ablation device 100 in relation to a tissue surface 3 can be
achieved. As shown in FIGS. 11, 31, 42, and 44, in one embodiment,
deflection of the ablation device 100 results in a therapeutic
level of contact, i.e., a substantially direct, uniform, and
sustainable contact between the ablation structure 101 of the
device 100 and the target tissue surface 3. For example, as shown
in FIGS. 31, 42, and 44, when the inflation member 105 is
sufficiently inflated, the resulting expanded profile of the
inflation member 105, which contacts the tissue surface 3, results
in contact by deflection between the tissue surface 3 and the
ablation structure 100. In these embodiments, suction can be
applied in combination with the inflation member 105 to achieve
contact between the ablation structure 101 and the tissue surface
3. Suction can be achieved through the endoscope 111 or through the
ablation device 100 to aid in collapsing the targeted tissue
surface 3 around the ablation structure 101.
[0155] In various embodiments, the inflation member 105 may be
compliant, non-compliant or semi-compliant. The inflation member
105 can be made of a thin, flexible, bladder made of a material
such as a polymer, as by way of non-limiting examples, polyimide,
polyurethane, or polyethylene terephthalate (PET). In one
embodiment, the inflation member is a balloon. Inflation of the
inflation member 105 can be achieved through the inflation line 113
using, for example, controlled delivery of fluid or gas expansion
medium. The expansion medium can include a compressible gaseous
medium such as air. The expansion medium may alternatively comprise
an incompressible fluid medium, such as water or a saline
solution.
[0156] As shown in FIGS. 12, 13, and 14, the inflation member 105
can be configured and arranged in a variety of ways to facilitate
deflection of the ablation device 100 in relation to a tissue
surface 3. For example, as shown in FIG. 12, the inflation member
105 can be eccentrically positioned in relation to the supporting
endoscope 111 as well as the housing 107 and the ablation structure
101. Alternatively, as shown in FIG. 13, the inflation member 105
can be positioned concentrically in relation to the supporting
endoscope 111 and the ablation structure 101 can be attached to the
inflation member 105 distally from the endoscope 111. In another
embodiment, as shown in FIG. 12, the inflation member 105 can be
positioned between the supporting endoscope 111 and the ablation
structure 101. The ablation structure 101 shown in FIGS. 12-14 can
cover a range of circumferential span of the endoscope 111
spanning, for example, from about 5 to 360 degrees when inflation
member 105 is deployed.
[0157] One method of ablating tissue in a targeted lesion region
can include a first step of advancing an ablation structure 101,
into the targeted lesion region. Next, the ablation structure 101
is deflected toward a lesion tissue surface. Finally, energy can be
applied to the ablation structure 101 to ablate the lesion.
[0158] In a further method, the step of supporting the ablation
structure 101 with an endoscope 111 includes inserting the
endoscope 111 into the ablation structure 101 (see for example,
FIGS. 1A-2B). In a related method, the ablation structure 101 is
supported by a sheath 103 (see FIGS. 26-28, 30, 31, 32 and 37) and
the step of inserting the endoscope 111 into the ablation structure
101 includes inserting the endoscope 111 into the sheath 103. In a
further related method, the step of inserting the endoscope 111
into the sheath 103 includes creating an opening in the sheath 103
(not shown).
[0159] In a particular method, a distal portion of a sheath 103
having a smaller outer diameter than a proximal portion of the
sheath 103, is adapted to be expanded when an endoscope 111 is
inserted into it.
[0160] In another method, the step of advancing the ablation
structure 101 into the gastrointestinal tract or lesion region
includes advancing the ablation structure 101 through a channel of
the endoscope 111 from either the endoscopes proximal or distal end
(as discussed below for FIGS. 34A, 35A and 36A). In yet another
method, the step of supporting the ablation structure 101 comprises
supporting the ablation structure 101 with a channel of the
endoscope (see as discussed below for FIGS. 34A, 35A, 36A, 37-39).
In a further method, a deflection structure or deflection member
150 is advanced through a channel of the endoscope 111 and the step
of deflecting the ablation structure 101 toward a tissue surface 3
includes deflecting the ablation structure 101 with the deflection
structure or deflection member 150.
[0161] As illustrated in FIGS. 34A, 35A, and 36A, variously adapted
and configured ablation structures 101 can fit within and be
conveyed through an endoscope internal working channel 211. In each
case, the ablation structure 101 and an accompanying deflection
mechanism can be conveyed through the internal working channel 211
in a dimensionally compacted first configuration that is capable of
expansion to a second radially expanded configuration upon exiting
the distal end 110 of the endoscope 111 (For example, see FIGS.
34A, 34B, 35A, 35B, 36A, and 36B).
[0162] As shown in FIG. 34B, in one embodiment, the deflection
mechanism is an inflation member 105, to which the ablation
structure 101 can be integrated within or mounted/attached to, for
example by etching, mounting or bonding. The inflation member 105
can be, for example, a compliant, non-compliant or semi-compliant
balloon.
[0163] As shown in FIGS. 35B and 35B, in another embodiment, the
deflection mechanism is an expandable member 209 that can expand to
a second desired arrangement and configuration. As shown in FIG.
35B, the expandable member 209, can be an expandable stent, frame
or cage device, to which an ablation structure 101 is mounted or
integrated. For example, where the expandable member 209 is a wire
cage, the wires can be a component of a bipolar circuit to provide
the ablation structure 101 feature. Alternatively, the cage can
have a flexible electrode circuit bonded or can be attached to an
outer or inner surface of the cage to provide an ablation structure
101 that is an electrode. As shown in FIG. 36B, the expandable
member 209, can be a folded or rolled series of hoops including or
having an attached ablation structure 101 that expands upon exiting
the endoscope distal end 110.
[0164] As further illustrated in FIGS. 37-39, the ablation
structure 101 can be supported with a channel of the endoscope 111.
In one embodiment as shown in FIGS. 37-39, an ablation device 100
includes a deflection member 150 that supports an attached housing
107 and ablation structure 101. As shown in FIG. 39, the endoscope
111 includes an internal working channel 211 suitable for advancing
or retreating the deflection member 150 which is connected to an
internal coupling mechanism 215 of the ablation device 100. FIGS.
37 and 39 both show a deflection member 150 including a bent region
of the deflection member 150 in a deployed position, wherein the
deflection member 150 bent region is positioned external to the
endoscope distal end 110. FIG. 38 shows the deflection member 150
in an undeployed position, wherein the deflection member 150 bent
region is positioned internal to the endoscope 111. The ablation
structure 101 is thus supported with a channel of the endoscope 111
(the internal working channel 211 of the endoscope 111) by way of
the deflection member 150 and the connected internal coupling
mechanism 215 of the ablation device 100.
[0165] In addition, when the deflection member 150 is advanced or
moved proximally or distally within the endoscope internal working
channel 211, the deflection member 150 is accordingly advanced
through a channel of the endoscope 111. In another implementation,
as shown in FIG. 42, wherein the deflection mechanism is an
inflatable member 105 (shown in a deployed configuration) coupled
to an inflation line 113, the inflation line 113 can be disposed
within the endoscope internal working channel 211. In yet another
implementation, both the inflatable member 105 (in an undeployed
configuration) and inflation line 113 can be advanced within the
internal working channel 211 either proximally or distally in
relation to the endoscope 111. Conductive wires 109 can pass
through the working channel (not shown) or outside as shown in FIG.
37.
[0166] As shown in FIG. 41, in another implementation the endoscope
111 includes an internal working channel 211 suitable for
supporting the ablation housing 107 and ablation structure 101
which are connected to an internal coupling mechanism 215 of the
ablation device 100. As such, the connected ablation structure 101
is supported within a channel of the endoscope 111. Additionally as
shown in FIG. 41, the housing 107 and ablation structure 101 can
further be supported by an external region of the endoscope 111,
wherein the internal coupling mechanism 215 is adapted and
configured to position the housing 107 in contact with the external
region of the endoscope 111. The internal coupling mechanism 215
can be cannulated (not shown) to facilitate use of the working
channel to aspirate and flow in fluids or air.
[0167] In another ablation method, an additional step includes
moving the ablation structure 101 with respect to the endoscope 111
within a lesion region. As illustrated in FIGS. 27, 28, 30, 32, and
47, and as discussed below, a sheath 103 of the ablation device 100
to which the ablation structure 101 is attached can enable moving
the ablation structure 101 with respect to the endoscope 111.
Further, as illustrated in FIGS. 34A, 35A, 36A, 37, 38, 39, and 41,
and discussed above, an internal working channel 211 of the
endoscope 111 through which at least a part of the ablation device
100 is disposed can enable moving the ablations structure 101 with
respect to the endoscope 111.
[0168] Referring to FIGS. 11, 31, 42, and 44, in yet another
method, the step of deflecting the ablation structure 101 toward a
tissue surface 3 includes inflating an inflation member 105 of the
ablation device 100 within a lesion region of a gastrointestinal
tract. The inflation member 105 can be arranged and configured to
be reversibly inflatable. The inflation member 105 can be inserted
along with the ablation structure 101 into an alimentary tract in a
collapsed configuration and expanded upon localization at a
pre-selected treatment area. In one implementation, the inflation
member 105 is a balloon. For example, in FIGS. 11, 31, 42, and 44
it is shown how deflecting the ablation structure 101 toward a
tissue surface 3 is achieved when the inflation member 105 is
inflated or deployed. As illustrated in FIGS. 11, 31, 42, and 44,
upon sufficient inflation, the inflation member 105 contacts a
tissue surface 3 consequently deflecting the ablation structure 101
which contacts an opposing tissue surface 3.
[0169] As shown in FIGS. 19B, 20, 35, 36 and discussed above, in a
further method, the step of deflecting the ablation structure 101
includes expanding a deflection structure or deflection member 150.
In one implementation, as shown in FIG. 19A the ablation device 100
includes a sheath 103, wherein the sheath 103 is arranged and
configured to receive the deflection member 150, the endoscope 111
and ablation structure 101 internally to the sheath 103. In one
implementation, the deflection member 150 is a shape memory alloy,
for example, Nitinol. The flexible extensions of the deflection
member 150 in this embodiment can be coupled to the endoscope, an
elastomeric sheath 115 of the ablation device 100 (shown in FIG.
19A) or any part of the device 100, including the ablation housing
107.
[0170] As shown in FIGS. 34, 35, 36, 37, 38, and 39, and discussed
above, in a further method, the step of deflecting the ablation
structure 101 includes moving a deflection structure or deflection
member 150.
[0171] Briefly, in each case moving the deflection 150 is used to
change the deflection member 150 from a non-deployed to a deployed
configuration. As shown in FIG. 23, in one embodiment, deflecting
the ablation structure 101 includes a flexing point in the ablation
structure 101, wherein the ablation structure 101 can deflect in
response to, for example, resistance met in contacting a tissue
surface 3.
[0172] As shown in FIGS. 43, 44, and 45A-45C and as discussed in
further detail below, in another method, the step of deflecting the
ablation structure 101 includes rotating, pivoting, turning or
spinning the ablation structure 101 with respect to the endoscope
111 along their respective and parallel longitudinal axes.
Deflection of the ablation structure 101 with respect to the
endoscope 111 can occur in combination with the endoscope 111
distal end 110 deflecting with respect to a target lesion site.
Also, the ablation structure 101 can deflect in combination with an
inflation member 105 used to achieve apposition of the ablation
device 100 to the tissue. In some embodiments, the step of
deflecting the ablation structure 101 may additionally include any
combination of the above disclosed deflecting steps.
[0173] As shown in FIGS. 19, 20, 21, 22, 34A, 34B, 35A, 35B, 36A,
36B, 46B, and 47, in another ablation method, an additional step
includes moving the ablation structure 101 from a first
configuration to a second radially expanded configuration. The
details regarding radial expansion of the ablation structure 101
shown in FIGS. 19, 20, 21, and 22 are described below, while the
details for FIGS. 34A, 34B, 35A, 35B, 36A, and 36B are described
above. Additionally, as shown in FIGS. 46B and 47 the ablation
structure 101 can be arranged in a first configuration wherein the
ablation structure 101 is coupled directly or alternatively through
an housing 107 (not shown) to an inflation member 105 attached to a
catheter 254. In an undeployed configuration as shown in FIGS. 46B
and 47, the non-inflated inflation member 105 and ablation
structure 101 have a relatively low profile in relation to the
endoscope 111. When deployed, the inflation member 105 moves the
ablation structure 101 to a second radially expanded configuration
(not shown).
[0174] As shown in FIGS. 15, 16, 40, 43, 44, 45A-45C, 46B, and 47,
in a further method, an additional step includes attaching the
ablation structure 101 to the endoscope 111. As shown in FIGS. 15
and 16, attachment of the ablation structure 101 to the endoscope
111 can also be by way of an elastomeric sheath 115 The elastomeric
sheath 115 can removably hold the ablation structure 101 in a
desired position on the endoscope 111. The elastomeric sheath 115
can be arranged and configured to fit over the endoscope distal end
110. As shown in FIGS. 15 and 16, the inflation member 105 can be
attached to the elastomeric sheath 115 or alternatively the
inflation member 105 can also act as the "elastomeric sheath" (not
shown).
[0175] In another method, the step of attaching the ablation
structure 101 to the endoscope 111 includes attaching the ablation
structure 101 to an outside surface of the endoscope.
Alternatively, the attaching step can include, for example,
attaching to an inside surface, an outside or inside feature of the
endoscope, or any combinations of the above. Lubricants such as
water, IPA, jelly, or oil may be use to aid attachment and removal
of the ablation device from the endoscope.
[0176] As shown in FIG. 41, in a further method, the step of
attaching the ablation structure 101 to the endoscope 111, includes
an ablation structure 101 having an attached rolled sheath 116,
wherein attaching the ablation structure 101 to the endoscope 111
includes unrolling the sheath 116 over an outside surface of the
endoscope 111. The rolled sheath 116 can additionally cover the
electrical connections 109 of the ablation device 100 along a
length of the endoscope 111 (see FIG. 41). In a related method, the
ablation structure 101 is attached to the endoscope 111 by an
attaching step including unrolling the rolled sheath 116 over an
outside surface of the endoscope 111 and part of the ablation
structure 101. This structure may also be used to mount the
ablation structure on one or more fingers of a user (as shown in
FIG. 60).
[0177] In another method, as shown in FIG. 40, the step of
attaching the ablation structure 101 to the endoscope 111 includes
attaching the ablation structure 101 to a channel of the endoscope.
As shown in FIG. 40, in one implementation, the housing 107 and
ablation structure 101 are coupled to an internal coupling
mechanism 215 that can be positioned within an internal working
channel 211 of the endoscope 111. The internal coupling mechanism
215 in FIG. 40 is shown as attached to the internal working channel
211 at the endoscope distal end 110. In this embodiment, the
housing 107 and ablation structure 101 are shown in alignment with
and coupled to an outside surface of the endoscope 111 near the
distal end 110.
[0178] In one method of ablating tissue in the alimentary tract,
the tissue surface 3 can include a first treatment area and
activation of the ablation structure 101 step can include
activation of the ablation structure 101 to ablate the first
treatment area, and further include moving the ablation structure
101 to a second area without removing the ablation structure 101
from the patient and activating the ablation structure 101 to
ablate the second tissue area 3. Moving, in this sense, refers to
moving the ablational structure to the locale of a target site, and
thereafter, further moving of the structure into a therapeutically
effected position can be performed variously by inflating a balloon
member, or deflection or inflating a deflection member, as
described in detail elsewhere. For example, two or more areas of
the tissue surface 3 of a target area can be ablated by directing
the ablation structure 101 to the first target region and then
activating the ablation structure 101 to ablate the tissue surface
3. Then, without removing the ablation structure 101 from the
patient, the ablation structure 101 can be directed to the second
target area for ablation of the appropriate region of the tissue
surface 3.
[0179] In general, in another aspect, an ablation device 100 is
provided that includes an ablation structure 101 removably coupled
to an endoscope distal end 110, and a deflection mechanism adapted
and configured to move the ablation structure 101 toward a tissue
surface 3 (see for example, FIGS. 5-19, 22, 22, 27-29, 30-32, 34A,
35A, 36A, 37, 38, 39, 42, 44, and 47).
[0180] In a related embodiment, the ablation device 100
additionally includes an ablation structure movement mechanism
adapted to move the ablation structure 101 with respect to the
endoscope 111. As discussed below and shown in FIGS. 26-28, and
30-32, the ablation structure movement mechanism can be a sheath
103 to which the ablation structure 101 is attached, wherein the
sheath 103 is arranged and configured to move the ablation
structure 101 with respect to an endoscope 111 received within the
sheath 103. Alternatively, as discussed above and shown in FIGS.
34A, 35A, 36A, and 37-39, the ablation structure movement mechanism
can be in the form of an internal coupling mechanism 215 of the
ablation structure 100, wherein the ablation structure is connected
to the internal coupling mechanism 215 and at least a portion of
the internal coupling mechanism 215 is disposed internally to the
endoscope.
[0181] In another embodiment, the ablation device 100 additionally
includes a coupling mechanism designed to fit over an outside
surface of an endoscope 111, to couple the ablation structure 101
with the endoscope 111. As discussed above, a spiral sheath 104, an
elastomeric sheath 115, a rolled sheath 116 and an internal
coupling mechanism as shown in FIGS. 15, 16, 40, and 41
respectively, are examples of such coupling mechanisms. In a
particular embodiment, the coupling mechanism includes a sheath 103
capable of supporting the ablation structure 101. The sheath 103
can be tubing, a catheter or other suitable elongate members. The
sheath 103 can be arranged and configured so that it can be moved
independently of an associated endoscope.
[0182] As shown in FIG. 41, in another embodiment, the sheath 103
can be arranged and configured as a rolled sheath 116 that can be
unrolled over the outside surface of the endoscope. In use, a
rolled sheath 116 connected to the ablation device 100, for example
at substantially near the proximal end of the housing 107 (from the
perspective of an operator of the device), can be unrolled from
such a position and continue to be unrolled toward the proximal end
112 of the endoscope 111 (see FIG. 47). In this way, the rolled
sheath 116 can be caused to contact and cover all or a portion of
the length of the endoscope 111 (not shown). Additionally, as the
rolled sheath 116 is unrolled along the endoscope 111, it can
sandwich the electrical connections 109 between the rolled sheath
116 and the endoscope 111 (see generally FIG. 41).
[0183] In another embodiment, as shown in FIGS. 30 and 31, the
sheath 103 can be arranged and configured to support a deflection
mechanism wherein the deflection mechanism includes a deflection
structure or deflection member 150. As illustrated in FIGS. 30 and
31, where the deflection member 150 is an inflation member 105, the
inflation member 105 can be directly attached to the sheath 103. As
shown in each case, the inflation member 105 is positioned opposite
the placement of the ablation structure 101, which is also attached
to the sheath 103. This configuration of the sheath 103 provides
support for the inflation member 105 and the ablation structure 101
irrespective of the positioning of the endoscope distal end 110.
For example, as shown in FIG. 30, the endoscope distal end 110 can
be positioned to provide a gap between the distal end 110 and a
distal end of the sheath 103 where the ablation structure 101 and
inflation member 105 are positioned. In contrast, as shown in FIG.
31 the endoscope distal end 110 can extend through and beyond the
distal end of the sheath 103.
[0184] In another embodiment, as shown in FIG. 26, the sheath 103
can be elongated. FIG. 26 illustrates a sheath including electrical
connections 109 and an inflation line 113. The sheath 103 may
include pneumatic and/or over extruded wires impregnated within the
sheath 103. In use, the sheath 103 can be introduced first into an
alimentary tract, wherein the sheath 103 serves as a catheter like
guide for introduction of the endoscope 111 within the sheath 103.
Alternatively, the endoscope 111 may be introduced first and
thereby serve as a guidewire for the sheath 103 to be introduced
over. FIG. 26 also shows attachment of an inflation member 105 to
the sheath 103, in an arrangement wherein the ablation structure
101 is attached to the inflation member 105 opposite the sheath 103
attachment point.
[0185] In embodiments shown in FIGS. 27 and 28, the sheath 103
includes an optically transmissive portion 158 adapted and
configured to cooperate with a visual channel of an endoscope 111.
For example, the sheath 103 may be made of clear, translucent or
transparent polymeric tubing including PVC, acrylic, and Pebax.RTM.
(a polyether block amide). As shown in FIG. 24, one component of an
endoscope 111 can be a visual channel 161 that provides visual
imaging of a tissue surface 3 as imaged from the endoscope distal
end 110. For example, the transmissive portion 158 can allow
visualization of the wall of an esophagus 3 through the
transmissive portion 158 of the sheath 103. As shown in FIG. 28 and
in the cross-section view provided in FIG. 29, the sheaths 103
shown in FIGS. 27 and 28, include an optically transmissive portion
158 arranged and configured to provide viewing of tissue surfaces 3
through the wall of the sheath 103, with the aid of an internally
disposed endoscope 111 having a visual channel 161. Also shown in
cross-section in FIG. 29 are portions of the sheath 103 through
which electrical connections 109 and an inflation line 113 can
pass. These features may be imbedded into the sheath 103 inner-wall
or attached to the sheath 103 inner wall. As shown in FIG. 27, the
sheath 103 including a transmissive portion 158 can extend past the
endoscope distal tip 110. Alternatively, as shown in FIGS. 27, 28,
and 31, the endoscope distal end 110 can extend distally past the
transmissive portion 158 of the sheath 103.
[0186] In another implementation, the transmissive portion 158 of
the sheath 103 can be reinforced structurally with coil or braid
elements incorporated therein to prevent ovalization and/or
collapsing of the sheath 103, particularly while deflecting the
ablation device 100.
[0187] In a further embodiment, the sheath 103 includes a slit 203
formed in a proximal portion of the sheath 103, the slit 203 being
designed to open to admit an endoscope distal end 110 into the
sheath 103. As shown in FIG. 32 the proximal portion of the sheath
103 can include a perforation region or slit 203. The slit 203 can
extend partially of fully along the length of the sheath 103. The
slit 203 enables the sheath 103 to be pulled back, or opened when,
for example introducing an endoscope 111 into the sheath 103. In
one implementation, as shown in FIG. 32, the sheath 103
additionally includes a locking collar 205 for locking the sheath
103 in a desired position in respect to the endoscope 111.
[0188] As shown in FIGS. 33A and 33B, the distal portion of the
sheath 103 can have a smaller outer diameter than a, proximal
portion of the sheath 103, the distal portion of the sheath 103
being adapted and configured to be expanded when an endoscope 111
is inserted into it (not shown). This embodiment can aid in
accessing an endoscope 111 in a case where the sheath 103 is
advanced first into a target site. Since the distal end of the
sheath 103 is smaller in diameter, but includes a slit 203, the
sheath 103 can accept a larger outside diameter endoscope 111
because when the endoscope 111 is advanced, the slit 203 of the
sheath 103 allows for widening of the sheath 103.
[0189] In general, in another aspect, a method of ablating tissue
in within the alimentary tract includes advancing an ablation
structure 101 into the alimentary tract while supporting the
ablation structure 101 with an endoscope 111. The endoscope distal
end 110 can be bent to move the ablation structure 101 into contact
with a tissue surface followed by activation of the ablation
structure 101 to ablate the tissue surface 3 (see e.g., FIG. 43).
In a particular embodiment, the ablation structure 101 includes a
plurality of electrodes and the activating step includes applying
energy to the electrodes.
[0190] In general, in another aspect the coupling mechanism is
designed to fit over an outside surface of an endoscope 111, to
couple the ablation structure 101 with the endoscope 111, rather
than being for example, a sheath (as discussed above), and is
adapted and configured to provide a certain freedom of movement to
the ablation structure 101, including but not limited to flexing
and/or rotating and/or pivoting with respect to the endoscope 111
when coupled to the endoscope 111. The freedom of movement is with
respect to one, two, or three axes, thereby providing one, two, or
three degrees of freedom. Non-limiting examples of suitable
coupling mechanisms include a flex joint, pin joint, U-joint, ball
joint, or any combination thereof. The following described coupling
mechanism embodiments advantageously provide for a substantially
uniform apposition force between a supporting endoscope 111 and an
ablation structure 101 when localized at a target tissue surface
3.
[0191] As shown in FIGS. 43, 44, 45A, and 45B, the coupling
mechanism can be a ring 250 attached to the housing 107 and the
endoscope 111, wherein the housing 107 is adapted and configured to
flex, rotate or pivot about the ring 250. Alternatively, the
coupling may be configured for hard held or finger mounted use. For
example, as illustrated in FIG. 43, where the ablation device 100
is coupled to a deflectable distal end 110 of an endoscope 111 by a
ring 250, when the device 100 is deflected toward the target tissue
surface 3, the housing 107 upon contact aligns the ablation
structure 101 with the tissue surface 3 by flexing, rotating or
pivoting about the ring 250 coupling. In these embodiments, the
endoscope and the housing that supports the ablation structure both
have their own longitudinal axis, and these axes are situated
parallel to each other. The coupling mechanism that attaches the
housing to the endoscope allows a pivoting movement between the
longitudinal axis of the housing and the longitudinal axis of the
endoscope. Advantageously, sufficient contact pressure provided by
deflection of the distal end 110 of the endoscope 101 can produce a
desired degree of contact between the ablation structure 101 and
the tissue surface 3, irrespective of the precise alignment of the
distal end 112 in respect to a plane of the tissue surface 3 to be
treated. For the purposes of this disclosure, a "desired degree of
contact", "desired contact", "therapeutic contact", or
"therapeutically effective contact" between the ablation structure
101 and the tissue surface 3, includes complete or
substantially-complete contact between all or a portion of a
predetermined target on the tissue surface 3 (e.g. a lesion or
lesions in the target site) by all or a portion of the ablation
structure 101.
[0192] As shown in FIG. 44, in a different yet related embodiment,
where the deflection mechanism of the ablation device 100 is an
inflatable member 105, a ring 250 coupling allows for flexing,
rotating or pivoting of the housing 107 and ablation structure 101.
As in the previous case, sufficient contact pressure provided
through deflection, here by the inflatable member 105, can produce
a desired degree of contact between the ablation structure 101 and
the tissue surface 3. Again, advantageously, the desired contact
can be achieved irrespective of the precise alignment of the
deflected endoscope 111 distal end 110 in respect to a plane of the
tissue surface 3 to be treated, because of the flexing, rotating or
pivoting provided by the ring 250 coupling.
[0193] As shown in FIG. 45A, in a related embodiment, the coupling
mechanism between the ablation device 100 and an endoscope 111 can
be an elastic band 252, wherein the housing 107 of the device 100
is flexibly coupled to the elastic band 252. For example, as
illustrated in FIG. 45C, where the ablation device 100 is coupled
to a distal end 110 of an endoscope 111 by an elastic band 252,
when the device 100 is deflected toward a tissue surface 3,
alignment between the housing 107 and accordingly the ablation
structure 101 and the tissue surface 3, can be achieved by flexing
about the elastic band 252 coupling. Once more, advantageously, the
desired contact can be achieved irrespective of the precise
alignment of the deflected endoscope's 111 distal end 110 in
respect to a plane of the tissue surface 3 to be treated, because
of the flexing capability provided by the elastic band 252
coupling.
[0194] As shown in FIG. 45A, in another related embodiment, the
coupling mechanism between the ablation device 100 and an endoscope
111 can be a combination of a ring 250 and an elastic band 252,
wherein the housing 107 of the device 100 is coupled to the elastic
band 252. For example, as illustrated in FIG. 45A, where the
ablation device 100 is coupled to a distal end 110 of an endoscope
111 by an elastic band 252, when the device 100 is deflected toward
a tissue surface 3 containing a lesion to be treated, alignment
between the housing 107 and accordingly the ablation structure 101,
and the tissue surface 3 by flexing, rotating or pivoting about the
ring 250 and the elastic band 252 coupling can be achieved. Again,
advantageously, the desired contact can be achieved irrespective of
the precise alignment of the deflected endoscope 111 distal end 110
in respect to a plane of the tissue surface 3 to be treated,
because of the flexing rotating or pivoting provided by the elastic
band 252 coupling.
[0195] In another embodiment, the ablation device 100 additionally
includes an alternative coupling mechanism between the ablation
device 100 and an endoscope 111 that is arranged and configured to
fit within a channel of an endoscope 111. The coupling mechanism
can be an internal coupling mechanism 215 and can be configured and
arranged to couple the ablation structure 101 within an internal
working channel 211 of an endoscope 111 (see FIG. 37 and as
discussed above).
[0196] As shown in FIGS. 34A, 34B, 35A, 35B, 36A, and 36B, in one
embodiment of such a coupling mechanism, the ablation structure 101
is adapted and configured to fit within the endoscope internal
working channel 211. Additionally, as shown in FIGS. 34A, 34B, 35A,
35B, 36A, and 36B, in a related embodiment, the deflection
mechanism is also adapted and configured to fit within the
endoscope internal working channel 211.
[0197] In each of the embodiments described above and shown in
FIGS. 34A, 34B, 35A, 35B, 36A, and 36B, after expansion of the
inflatable member 105 or expandable member 209 and subsequent
treatment of a target tissue 3, the coupling means can further
serve as a means to draw, pull or retrieve the ablation structure
101 and deflection mechanism back into the endoscope internal
working channel 211. Furthermore, in addition to providing coupling
of the ablation structure 101 with the endoscope internal working
channel 112, the coupling mechanism can include electrical
connections 109 to provide energy to the ablation structure
101.
[0198] In a related embodiment, again wherein the ablation device
100 additionally includes a coupling mechanism adapted and
configured to fit within a channel of an endoscope 111, the
coupling mechanism can include a shape memory member and the
deflection mechanism can include a bent portion of the shape memory
member. As shown in FIGS. 37-39, the coupling mechanism can be an
internal coupling mechanism 215. As shown, the internal coupling
mechanism 215 can be disposed within an endoscope internal working
channel 211 and extend beyond the endoscope distal end 100.
Additionally, the internal coupling mechanism 215 can be connected
to a deflection mechanism that is a deflection member 150. The
deflection member 150 can include a bent portion and can be
connected to the housing 107. As shown in FIG. 38 and discussed
above, the bent portion of the deflection member 150 can be
disposed within the endoscope internal working channel 211, causing
the ablation structure 101 to move into a non-deployed position.
Upon advancing the internal coupling mechanism 215 toward the
endoscope distal end 110, the shape memory nature of the deflection
member 150 facilitates deployment of the ablation structure 101 to
a position suitable for ablation.
[0199] In general, in one aspect, the ablation structure 101 of the
ablation device 100 includes an optically transmissive portion 158
adapted and configured to cooperate with a visual channel of an
endoscope 111. As shown in FIGS. 27-31 and discussed above, the
optically transmissive portion 158 can be a sheath 103 of the
ablation device 100.
[0200] In one embodiment, the ablation structure 101 of the
ablation device 100 is further adapted and configured to move from
a first configuration to a second radially expanded configuration.
As shown in FIGS. 19-22, the ablation structure 101 and housing 107
can be designed to reversibly move from a first less radially
expanded configuration (see FIGS. 20 and 21) to a second radially
expanded configuration useful for ablation. Foldable or deflectable
configurations that provide for reversible radial expansion of the
housing 107 and the ablation structure 101 can facilitate access to
tissue surfaces because of reduced size. Additionally, foldable or
deflectable configurations are helpful in regard to cleaning,
introduction, retrieval, and repositioning of the device in the
lesion containing regions.
[0201] The ablation device 100 shown in FIGS. 19B and 20 includes
an ablation structure actuator 152 arranged and configured to move
the ablation structure 101 from the first configuration (see FIG.
20) to a second radially-expanded configuration (see FIG. 21). As
shown (FIGS. 19B and 20), the actuator 152 can be elongate and
designed to work with a receiver 154 arranged and configured to
receive the actuator 152. The actuator 152 can be a wire, rod or
other suitable elongate structure. Alternatively, the actuator 152
can be a hydraulic actuation means with or without a balloon
component. In a particular embodiment, the actuator 152 is a
stiffening wire.
[0202] As illustrated in FIG. 20, before the actuator 152 is
disposed within the portion of receiver 154 attached to the housing
107, both the housing 107 and the ablation structure 101 are in a
first position having a first configuration. As illustrated in FIG.
21, after the actuator 152 is partially or fully introduced into
the receiver 154, the housing 107 and the ablation structure 101
are consequently changed to a second radially expanded
configuration relative to the first configuration. Introduction of
the actuator 152 into the receiver 154 can force the portions of
the housing 107 and ablation structure 101 flanking the receiver
154 to expand radially (see FIG. 19). In one embodiment, the
housing 107 is heat set in a flexed first configuration suitable
for positioning the ablation device 100 near a target tissue
surface 3. After a target tissue surface 3 has been reached, the
actuator 152 can be introduced into the receiver 154 to achieve the
second radially expanded configuration which is useful for ablation
of the tissue surface 3.
[0203] In a related alternative embodiment, the housing 107 and
ablation structure 101 include an unconstrained shape that is
radially expanded and includes one or more flex points to allow for
collapsed or reduced radial expansion when positioned distally to
the distal end 110 of an endoscope 111 and compressed by an
elastomeric sheath 115 (not shown).
[0204] As shown in FIGS. 21 and 22, in another embodiment, the
ablation structure 101 of the ablation device 100 is adapted and
configured to move from a first configuration to a second radially
expanded configuration wherein the ablation device 100 further
includes an expandable member 156. The expandable member 156 can be
positioned between the housing 107 and the endoscope 111, where in
unexpanded form, the ablation structure 101 is accordingly
configured in a first configuration. Upon expansion of the
expandable member 156, the ablation structure 101 configuration is
changed to a second radially expanded configuration (see FIG.
21).
[0205] In one embodiment, the deflection mechanism of the ablation
device 100 includes an inflatable inflation member 105. As shown in
FIGS. 11, 21, 22, 25B, 27, 28, 30, 31, 34A, 34B, 42, 44, 46, and 47
and discussed above, the inflation member 105 can facilitate
deflection of the device 100 in relation to a tissue surface 3.
[0206] In another embodiment, the deflection mechanism includes an
expandable member 156 (see FIGS. 35B and 36B, discussed in detail
above). As shown in FIG. 35B, the expandable member 209, can be an
expandable stent, frame or cage device. As shown in FIG. 36B, the
expandable member 209, can be an expanded series of connected hoops
that can be folded or rolled prior to expansion.
[0207] In another advantageous embodiment, the ablation device 100
further comprises a torque transmission member adapted and
configured to transmit torque from a proximal end of the endoscope
111 to the ablation structure 101 to rotate the ablation structure
101 about a central axis of the endoscope 111. In a particular
embodiment, the torque transmission member includes first and
second interlocking members adapted to resist relative movement
between the endoscope 111 and the ablation structure 101 about the
central axis. As shown in FIGS. 46B, 46C, and 47, in one embodiment
the first interlocking member is a key 258 and the second
interlocking member is a keyway 256. In one embodiment, the first
interlocking member is attached to a sheath 103 surrounding the
endoscope 111 and the second interlocking member is attached to a
catheter 254 supporting the ablation structure 101. For example, as
shown in FIGS. 46B, 46C, and 47, the key 258 can be attached to a
sheath 103 surrounding the endoscope 111 and the keyway 256 can be
attached to a catheter 254 supporting the ablation structure 101.
In a further related embodiment, the catheter 254 and sheath 103
are arranged and configured for relative movement along the central
axis of the endoscope 111. The sheath 103 can be, for example, an
elastomeric sheath wherein the key 258 is attached to the outside
of the sheath 103 substantially along a longitudinal axis of the
sheath 103 (see FIG. 46C). In use, this embodiment provides for a
1-to-1 torque transmission of the ablation device 100 endoscope
assembly 111 when the endoscope proximal end 112 is manipulated,
while also providing for positioning of the ablation structure 101
either proximal or distal to the endoscope distal end 110 in situ.
Additionally, the sheath 103 can be pre-loaded into the catheter
254 or loaded separately.
[0208] In general, in one aspect, an ablation device 100 is
provided including an ablation structure 101, and a coupling
mechanism adapted to removably couple the ablation structure 101 to
a distal end 110 of an endoscope 111 and to permit the ablation
structure 101 to rotate and/or pivot with respect to the endoscope
when coupled to the endoscope. Various related embodiments wherein,
for example, the coupling mechanism comprises a ring 250 and the
ablation structure 101 is adapted to rotate and/or pivot about the
ring 250; wherein the coupling mechanism comprises an elastic band
252 adapted to flex to permit the ablation structure 101 to rotate
and/or pivot; wherein the ablation device 100 further includes a
deflection mechanism adapted and configured to move the ablation
structure 101 toward a tissue surface 3; and, wherein such a
deflection mechanism includes an inflatable member, have been set
out in detail above.
[0209] FIGS. 56A and 56B provide views of an ablational device with
an ablational surface on a hinge 159 which acts in a manner similar
to mechanism depicted in FIG. 43, and which allows a free pivoting
movement of the ablational surface between its longitudinal axis
and the longitudinal axis of an endoscope. FIG. 56A shows the
device with the ablational surface 101 oriented in parallel with
the endoscope, the surface having made contact with the inner
surface of a gastrointestinal luminal wall 5 at a desired target
area. The ablation surface 101 is supported by a deflection member
150 that can be expressed from a working channel, and withdrawn
back into a working channel within the endoscope. FIG. 56B shows
the device with the longitudinal axis of the ablational surface 101
oriented at about a right angle with respect to the longitudinal
axis of the endoscope. This pivoting as a passive response of the
ablational surface 101, as it easily rotates on hinge 159 through a
flexion range of 0 degrees (parallel to the endoscope 111) to about
170 degrees. As shown, the angle of the surface is about 90 degrees
with respect to the endoscope.
[0210] FIG. 59 is a perspective view of a hand held ablation
therapy device 500. The hand held device 500 includes an electrode
array 101 mounted on a substrate 502. Leads 109 attach the
electrode array 101 to a generator and control system (not shown)
as described above. The substrate 502 may be used directly by a
user or a handle (not shown) may be provided. In addition, the
substrate 502 may be a malleable material so that it may deform
into the contours of a target site for providing therapeutic
contact with the target site or lesion. The substrate 502 may be
formed from foam, sponge or other compliant material, or be a
compliant container filled with elastomeric or gel. The device may
be a sponge or other compliant material that is coated with
conductive material and then attached to leads 109. The conductive
compliant material becomes the ablation structure. Such an ablation
structure would be highly compliant to the target site anatomy.
Suitable insulation or mounting structure may be provided to allow
the device to be hand held or mounted. Alternatively, the substrate
502 may also be a heat set material. In use, the user may apply
pressure directly to the substrate 502 in order to increase contact
between the electrode array 101 and the target lesion.
[0211] FIG. 60 is a perspective view of a finger-mountable ablation
therapy device 550. The ablation device 550 includes an electrode
array 101 on a band 555 mounted on a finger 19. Leads 109 attach
the electrode array 101 to a generator and control system (not
shown) as described above. Insulation is provided between the
electrode array 101 and the finger 19. The device 550 may also be
sized to fit more than one finger or in different sized fingers
such as male and female finger sizes. The band 555 may be elastic
or inelastic. Alternatively, the finger mounted device 550 may be
configured as part of a glove worn by the user. In use, the user
may direct the ablation therapy by pressure or manipulation of the
finger 19 under direct visualization and with tactile feedback.
[0212] As described above, embodiments of the present invention may
be used for ablation of benign, pre-cancerous and early stage
lesions that originate within the epithelium and are limited to the
mucosal layer of the gastrointestinal tract. Several specific
methods will now be described in turn.
[0213] In one aspect, there is a method of providing ablation based
therapy in a target area having a cervical inlet patch within a
portion of the proximal esophagus. The method includes the steps
of: manipulating a portion of the proximal esophagus to expose the
target area and deploying an ablation device into contact with the
target area. Next there are the steps of delivering ablative energy
to a tissue surface in the target area and then controlling the
delivery of ablative energy to the tissue surface and layers of the
target area. The manipulating step may also include identifying a
cervical inlet patch within the target area.
[0214] The method may also include additional steps such as
continuing the manipulating step to expose the target area during
the delivering and controlling steps; removing debris from the
target area after the controlling step; removing debris from the
target area after performing the controlling step more than once or
evaluating the target area after the delivering energy step.
[0215] Additionally, the method may also include a controlling step
for delivery of an energy density within the range of 10-15
J/cm.sup.2 or, sufficient ablative energy to achieve ablation in
one fraction of the tissue target surface and delivering
insufficient ablative energy to achieve ablation to another
fraction of the target tissue surface, delivering ablative energy
without an electrode structure penetrating tissue in the target
area or controlling the delivery of ablative energy within the
target tissue surface to provide sufficient treatment to achieve
ablation within the cercal inlet patch and yet provide insufficient
energy to other tissue layers beneath the cervical inlet patch.
[0216] The method of treating a cervical inlet patch may also
include controlling the delivery of ablative energy across the
surface and into tissue layers in the target area is such that some
fraction of the tissue volume is ablated and another fraction of
the tissue volume is not ablated. Alternatively, the method may
include controlling the delivery of energy into target tissue
layers consists of ablating: a fraction of tissue in the epithelial
layer of the cervical inlet patch; a fraction of tissue in the
epithelial layer and the lamina propria of the cervical inlet
patch; a fraction of cervical inlet patch tissue in the epithelial
layer, the lamina propria, and the muscularis mucosae; a fraction
of cervical inlet patch tissue in the epithelial layer, the lamina
propria, the muscularis mucosae, and the submucosa; and/or
delivering energy in an ablation pattern configured to conform to a
cervical inlet patch.
[0217] In additional aspects, the controlling step includes
adjusting the controlling step based on a feedback control of the
energy delivery to provide any of a specific power, a power
density, an energy level, an energy density, a circuit impedance,
target tissue temperature, a number of applications of energy, or a
pressure of application against the tissue. The deploying step may
also include moving the ablation structure into therapeutic contact
with the target area prior to the delivering energy step. In this
context, the moving step may also include expanding an expandable
member to enhance the therapeutic contact with the target tissue.
In addition, the moving step may include operating a deflection
mechanism to enhance the therapeutic contact with the target
tissue.
[0218] In another alternative method, there is a method of
providing ablation based therapy to a target area in a stomach
containing intestinal metaplasia, intra-epithelial neoplasia,
and/or early gastric cancer, hereafter referred to as "abnormal
gastric tissue." The method includes the steps of manipulating a
portion of the stomach to expose the target area and then deploying
an ablation device into contact with the target area. Next, there
are the steps of delivering ablative energy to a tissue surface in
the target area controlling the delivery of ablative energy to the
tissue surface and layers of the target area. In one aspect, the
manipulating step includes identifying the region of abnormal
gastric tissue within the target area after the manipulating
step.
[0219] In another aspect, the method of treating abnormal gastric
tissue may include continuing the manipulating step to expose the
target area during the delivering and controlling steps; removing
debris from the target area after the controlling step; and
removing debris from the target area after performing the
controlling step more than once and evaluating the target area
after the delivering energy step.
[0220] In other embodiments, the delivering step includes
delivering ablative energy without an electrode structure
penetrating tissue in the target area or delivering energy in an
ablation pattern configured to conform to the region of abnormal
gastric tissue within the target area. In still other embodiments,
the advancing step includes moving the ablation structure into
therapeutic contact with the target area prior to the delivering
energy step. Moving the ablation structure may include, for
example, expanding an expandable member to enhance the therapeutic
contact with the target tissue or operating a deflection mechanism
to enhance the therapeutic contact with the target tissue.
[0221] In other aspects of the method of treating abnormal gastric
tissue, the controlling step delivers an energy density of more
than 10 J/cm.sup.2 or higher. In other aspects, the controlling
step includes delivering sufficient ablative energy to achieve
ablation in one fraction of the tissue target surface and
delivering insufficient ablative energy to achieve ablation to
another fraction of the target tissue surface. In still another
variation, the controlling step includes controlling the delivery
of ablative energy from the target tissue surface with sufficient
energy to achieve ablation within the region of abnormal gastric
tissue within the target area and insufficient energy is delivered
to other target tissue layers beneath the region of abnormal
gastric tissue within the target area. In still another variation,
controlling the delivery of ablative energy across the surface and
into tissue layers in the target area is such that some fraction of
the tissue volume is ablated and another fraction of the tissue
volume is not ablated. In another aspect, controlling the delivery
of energy into target tissue layers consists of ablating a fraction
of tissue in the epithelial layer of the region of abnormal gastric
tissue within the target area. In still another aspect, controlling
the delivery of energy into target tissue layers consists of
ablating a fraction of tissue in the epithelial layer and the
lamina propria of the region of abnormal gastric tissue within the
target area. In another aspect, controlling the delivery of energy
into the tissue layers consists of ablating a fraction of the
region of abnormal gastric tissue within the target area tissue in
the epithelial layer, the lamina propria, and the muscularis
mucosae. In another variation, controlling the delivery of energy
into tissue layers consists of ablating a fraction of abnormal
gastric tissue within the target area in the epithelial layer, the
lamina propria, the muscularis mucosae, and the submucosa. In still
another variation, the controlling step includes adjusting the
controlling step based on a feedback control of the energy delivery
to provide any of a specific power, a power density, an energy
level, an energy density, a circuit impedance, target tissue
temperature, a number of applications of energy, or a pressure of
application against the tissue.
[0222] In another alternative method, there is a method of
providing ablation based therapy to a target area in an esophagus
having a region of a squamous intra-epithelial neoplasia and/or
early cancer of the esophagus, hereafter referred to as "abnormal
esophageal tissue". The method of providing ablation based therapy
to a target area in an esophagus having a region of abnormal
esophageal tissue within the target area includes the step of
identifying the region of a abnormal esophageal tissue within the
target area. Next, there is the step of advancing an ablation
device into contact with the target area and delivering ablative
energy to a tissue surface in the target area. Next, there is the
step of controlling the delivery of ablative energy to the tissue
surface and layers of the target area.
[0223] The method of treating abnormal esophageal tissue may also
include additional steps such as: removing debris from the target
area after the controlling step, removing debris from the target
area after performing the controlling step more than once or
evaluating the target area after the delivering energy step.
[0224] In still other embodiments, the advancing step includes
moving the ablation structure into therapeutic contact with the
target area prior to the delivering energy step. Moving the
ablation structure may include, for example, expanding an
expandable member to enhance the therapeutic contact with the
target tissue or operating a deflection mechanism to enhance the
therapeutic contact with the target tissue.
[0225] In one aspect, the delivery step includes delivering energy
nearly circumferentially about the esophagus to a region of
abnormal esophageal tissue within a nearly circumferential target
area in the esophagus. Alternatively, the delivering energy step
includes delivering energy less than circumferentially about the
esophagus to a region of a squamous intra-epithelial neoplasia
within a less than circumferential target area in the esophagus. In
another aspect, the delivering ablative energy step includes
delivering ablative energy without an electrode structure
penetrating tissue in the target area. In still another variation,
the delivering energy step includes delivery in an ablation pattern
configured to conform to the region of abnormal esophageal tissue
within the target area.
[0226] In still another variation of the method to treat abnormal
esophageal tissue within a target region, the controlling step
delivers a power density in the range of 10 to 15 J/cm.sup.2. In
still other variations, the controlling step includes delivering
sufficient ablative energy to achieve ablation in one fraction of
the tissue target surface and delivering insufficient ablative
energy to achieve ablation to another fraction of the target tissue
surface. In still another variation, the controlling step is
controlling the delivery of ablative energy from the target tissue
surface with sufficient energy to achieve ablation within the
region of a abnormal esophageal tissue in the target area and
insufficient energy is delivered to other target tissue layers
beneath the region of abnormal esophageal tissue within the target
area. In still another variation, the controlling step is
controlling the delivery of ablative energy across the surface and
into tissue layers in the target area is such that some fraction of
the tissue volume is ablated and another fraction of the tissue
volume is not ablated. In still another variation, the controlling
step is controlling the delivery of energy into target tissue
layers consists of ablating a fraction of tissue in the epithelial
layer of the region of abnormal esophageal tissue within the target
area. In still another variation, the controlling step is
controlling the delivery of energy into target tissue layers
consists of ablating a fraction of tissue in the epithelial layer
and the lamina propria of the region of abnormal esophageal tissue
within the target area. In still another variation, the controlling
step is controlling the delivery of energy into the tissue layers
consists of ablating a fraction of the region of abnormal
esophageal tissue within the target area tissue in the epithelial
layer, the lamina propria, and the muscularis mucosae. In still
another variation, the controlling step is controlling the delivery
of energy into tissue layers consists of ablating a fraction of
abnormal esophageal tissue within the target area in the epithelial
layer, the lamina propria, the muscularis mucosae, and the
submucosa. In still another variation, there is a step of adjusting
the controlling step based on a feedback control of the energy
delivery to provide any of a specific power, a power density, an
energy level, an energy density, a circuit impedance, target tissue
temperature, a number of applications of energy, or a pressure of
application against the tissue.
[0227] In another alternative embodiment, there is a method of
providing ablation based therapy in a target area having a region
of leukoplakia within the oral and/or pharyngeal cavity herein
after referred to as leukoplakia. The method treating leukoplakia
includes the steps of manipulating a portion of the oral and
pharyngeal cavity to expose the target area and then deploying an
ablation device into contact with the target area. Next, there is
the step of delivering ablative energy to a tissue surface in the
target area followed by the step of controlling the delivery of
ablative energy to the tissue surface and layers of the target
area.
[0228] The manipulating step may also include identifying a region
of leukoplakia within the target area. The delivering step may also
include delivering ablative energy without an electrode structure
penetrating tissue in the target area. The delivering energy step
may also include delivering energy in an ablation pattern
configured to conform to a region of leukoplakia. Additionally, the
method may include additional steps such as: continuing the
manipulating step to expose the target area during the delivering
and controlling steps; removing debris from the target area after
the controlling step; removing debris from the target area after
performing the controlling step more than once or evaluating the
target area after the delivering energy step.
[0229] Additionally, the method of treating leukoplakia may include
a controlling step that delivers a power density within the range
of 10-15 J/cm.sup.2. Alternatively, the controlling step may
include delivering sufficient ablative energy to achieve ablation
in one fraction of the tissue target surface and delivering
insufficient ablative energy to achieve ablation to another
fraction of the target tissue surface. In another variation, the
controlling step includes controlling the delivery of
ablativeenergy from the target tissue surface with sufficient
energy to achieve ablation within the region of leukoplakia and
insufficient energy is delivered to other target tissue layers
beneath the region of leukoplakia. In another variation, the
controlling step includes controlling the delivery of ablative
energy across the surface and into tissue layers in the target area
is such that some fraction of the tissue volume is ablated and
another fraction of the tissue volume is not ablated. In another
variation, the controlling step includes controlling the delivery
of energy into target tissue layers consists of ablating a fraction
of tissue in the epithelial layer of the region of leukoplakia. In
another variation, the controlling step includes controlling the
delivery of energy into target tissue layers consists of ablating a
fraction of tissue in the epithelial layer and the lamina propria
of the region of leukoplakia. In another variation, the controlling
step includes controlling the delivery of energy into the tissue
layers consists of ablating a fraction of the region of leukoplakia
tissue in the epithelial layer, the lamina propria, and the
muscularis mucosae. In another variation, the controlling step
includes controlling the delivery of energy into tissue layers
consists of ablating a fraction of the region of leukoplakia tissue
in the epithelial layer, the lamina propria, the muscularis
mucosae, and the submucosa. In another variation, the controlling
step includes adjusting the controlling step based on a feedback
control of the energy delivery to provide any of a specific power,
a power density, an energy level, an energy density, a circuit
impedance, target tissue temperature, a number of applications of
energy, or a pressure of application against the tissue.
[0230] In an alternative method of treating leukoplakia, the
deployment includes moving the ablation structure into therapeutic
contact with the target area prior to the delivering energy step.
In one aspect, the moving step includes expanding an expandable
member to enhance the therapeutic contact with the target tissue.
In another aspect, the moving step includes operating a deflection
mechanism to enhance the therapeutic contact with the target
tissue. In still another aspect, the moving step further includes
deforming the ablation structure to at least partially conform to
the region of leukoplakia. In still another aspect, there is a step
of placing the ablation structure on a finger of a user prior to
the advancing step and keeping the ablation structure on the finger
of the user during the delivering an controlling steps. This may
also be a handheld ablation device. Additionally, the deploying
step is performed using a hand held ablation device under direct
visualization of the user.
[0231] In another alternative method, there is a method of
providing ablation based therapy to a target area in a colon and/or
rectum having a region of one or more flat-type polyps within the
target area. The method includes the steps of manipulating a
portion of the colon to expose the target area and deploying an
ablation device into contact with the target area. Next, there is
the step of delivering ablative energy to a tissue surface in the
target area; and then controlling the delivery of ablative energy
to the tissue surface and layers of the target area.
[0232] In one alternative aspect, the manipulating step includes
identifying the region of one or more flat-type polyps within the
target area after the manipulating step. The method may also
include additional steps such as: continuing the manipulating step
to expose the target area during the delivering and controlling
steps; removing debris from the target area after the controlling
step; removing debris from the target area after performing the
controlling step more than once; evaluating the target area after
the delivering energy step.
[0233] In still other aspects, the delivering ablative energy step
includes delivering ablative energy without an electrode structure
penetrating tissue in the target area. The delivering energy step
may also include delivering energy in an ablation pattern
configured to conform to the region of one or more flat-type polyps
within the target area. In another aspect, the delivering step
includes delivering ablative energy to a tissue surface containing
residual flat-type polyp tissue in the target area where a partial
or complete polypectomy has been performed.
[0234] In another aspect of a method of treating a region of one or
more flat-type polyps within the target area, the controlling step
delivers a power density of 10 J/cm.sup.2 or greater. In another
variation, the controlling step includes delivering sufficient
ablative energy to achieve ablation in one fraction of the tissue
target surface and delivering insufficient ablative energy to
achieve ablation to another fraction of the target tissue surface.
In another variation, the controlling step includes controlling the
delivery of ablative energy from the target tissue surface with
sufficient energy to achieve ablation within the region of one or
more flat-type polyps within the target area and insufficient
energy is delivered to other target tissue layers beneath the
region of one or more flat-type polyps within the target area. In
another variation, the controlling step includes controlling the
delivery of ablative energy across the surface and into tissue
layers in the target area is such that some fraction of the tissue
volume is ablated and another fraction of the tissue volume is not
ablated. In another variation, the controlling step includes
controlling the delivery of energy into target tissue layers
consists of ablating a fraction of tissue in the epithelial layer
of the region of one or more flat-type polyps within the target
area. In another variation, the controlling step includes
controlling the delivery of energy into target tissue layers
consists of ablating a fraction of tissue in the epithelial layer
and the lamina propria of the region of one or more flat-type
polyps within the target area. In another variation, the
controlling step includes controlling the delivery of energy into
the tissue layers consists of ablating a fraction of the region of
one or more flat-type polyps within the target area tissue in the
epithelial layer, the lamina propria, and the muscularis mucosae.
In another variation, the controlling step includes controlling the
delivery of energy into tissue layers consists of ablating a
fraction of the region of one or more flat-type polyps within the
target area in the epithelial layer, the lamina propria, the
muscularis mucosae, and the submucosa. In another variation, the
controlling step includes adjusting the controlling step based on a
feedback control of the energy delivery to provide any of a
specific power, a power density, an energy level, an energy
density, a circuit impedance, target tissue temperature, a number
of applications of energy, or a pressure of application against the
tissue.
[0235] In still another variation, the method includes an advancing
step with moving the ablation structure into therapeutic contact
with the target area prior to the delivering energy step. In one
alternative, the moving step includes expanding an expandable
member to enhance the therapeutic contact with the target tissue.
In another aspect, the moving step includes operating a deflection
mechanism to enhance the therapeutic contact with the target
tissue.
[0236] In another aspect, there is a method of providing ablation
based therapy in an anal target area having a region of abnormal
anal tissue. As used herein, abnormal anal tissue refers to anal
intraepithelial neoplasia and/or early anal cancer. The method
includes the steps of manipulating a portion of the anal canal to
expose the target area and deploying an ablation device into
contact with the target area. Next, there are the steps of
delivering ablative energy to a tissue surface in the target area
and then controlling the delivery of ablative energy to the tissue
surface and layers of the target area. The method may include
additional steps such as: continuing the manipulating step to
expose the target area during the delivering and controlling steps;
removing debris from the target area after the controlling step;
removing debris from the target area after performing the
controlling step more than once; or evaluating the target area
after the delivering energy step. In addition, the manipulating
step may include identifying a region of abnormal anal tissue
within the target area.
[0237] In still other variations, the step of delivering ablative
energy includes delivering ablative energy without an electrode
structure penetrating tissue in the target area. In another
variation, the delivering energy step includes delivering energy in
an ablation pattern configured to conform to a region of
intraepithelial neoplasia.
[0238] In still other aspects, the method of treating abnormal anal
tissue includes a method where the controlling step delivers a
power density within the range of 10-15 J/cm.sup.2. In another
variation, the controlling step includes delivering sufficient
ablative energy to achieve ablation in one fraction of the tissue
target surface and delivering insufficient ablative energy to
achieve ablation to another fraction of the target tissue surface.
In another variation, the controlling step includes controlling the
delivery of ablative energy from the target tissue surface with
sufficient energy to achieve ablation within the region of abnormal
anal tissue and insufficient energy is delivered to other target
tissue layers beneath the region of abnormal anal tissue. In
another variation, the controlling step includes controlling the
delivery of ablative energy across the surface and into tissue
layers in the target area is such that some fraction of the tissue
volume is ablated and another fraction of the tissue volume is not
ablated. In another variation, the controlling step includes
controlling the delivery of energy into target tissue layers
consists of ablating a fraction of tissue in the epithelial layer
of the region of abnormal anal tissue. In another variation, the
controlling step includes controlling the delivery of energy into
target tissue layers consists of ablating a fraction of tissue in
the epithelial layer and the lamina propria of the region of
abnormal anal tissue. In another variation, the controlling step
includes controlling the delivery of energy into the tissue layers
consists of ablating a fraction of the region of abnormal anal
tissue in the epithelial layer, the lamina propria, and the
muscularis mucosae. In another variation, the controlling step
includes controlling the delivery of energy into tissue layers
consists of ablating a fraction of the region of abnormal anal
tissue in the epithelial layer, the lamina propria, the muscularis
mucosae, and the submucosa. In another variation, the controlling
step includes adjusting the controlling step based on a feedback
control of the energy delivery to provide any of a of a specific
power, a power density, an energy level, an energy density, a
circuit impedance, target tissue temperature, a number of
applications of energy, or a pressure of application against the
tissue.
[0239] In another variation of the method of treating abnormal anal
tissue, the deployment step includes moving the ablation structure
into therapeutic contact with the target area prior to the
delivering energy step. In another variation, moving step includes
expanding an expandable member to enhance the therapeutic contact
with the target tissue. In still another embodiment, the moving
step includes operating a deflection mechanism to enhance the
therapeutic contact with the target tissue. In still another
alternative, the moving step includes deforming the ablation
structure to at least partially conform to the region of abnormal
anal tissue. In another alternative, the method includes placing
the ablation structure on a finger of a user prior to the advancing
step and keeping the ablation structure on the finger of the user
during the delivering an controlling steps. In another alternative,
the deploying step is performed using a hand held ablation device
under direct visualization.
[0240] While most embodiments described herein have made use of
radiofrequency energy as an exemplary ablational energy, and
consequently have made use of electrodes as an energy transmitting
element, it should be understood that these examples are not
limiting with regard to energy source and energy delivery or
transmitting elements. As also described herein, other forms of
energy, as well as cryoablating approaches, may provide for
ablation of target areas in such a manner that ablation is
fractional or partial, as described herein, where some portions of
target area tissue are ablated, and some portions of target area
tissue are not substantially ablated.
Terms and Conventions
[0241] Unless defined otherwise, all technical terms used herein
have the same meanings as commonly understood by one of ordinary
skill in the art of ablational technologies. Specific methods,
devices, and materials are described in this application, but any
methods and materials similar or equivalent to those described
herein can be used in the practice of the present invention. While
embodiments of the invention have been described in some detail and
by way of exemplary illustrations, such illustration is for
purposes of clarity of understanding only, and is not intended to
be limiting. Still further, it should be understood that the
invention is not limited to the embodiments that have been set
forth for purposes of exemplification, but is to be defined only by
a fair reading of claims that are appended to the patent
application, including the full range of equivalency to which each
element thereof is entitled.
* * * * *